¶ 25. dissenting. The majority errs in finding ambiguity where none exists. There is only one reasonable interpretation of the contract language at issue in this case — the interpretation advanced by grievant. Grievant is plainly entitled to receive an increase in pay of “at least 5%” after being slotted into the appropriate step. I therefore dissent.
¶ 26. As the majority recognizes, our goal in interpreting contracts is to implement the parties’ intent. In re Adelphia Bus. Solutions of Vt., Inc., 2004 VT 82, ¶ 7, 177 Vt. 136, 861 A.2d 1078. We presume that the parties’ intent “is reflected in the contract’s language when that language is clear,” id., and clear language must be enforced according to its terms. Isbrandtsen v. N. Branch Corp., 150 Vt. 575, 579, 556 A.2d 81, 84 (1988). We will find ambiguity only if “a writing in and of itself supports a different interpretation from that which appears when it is read in light of the surrounding circumstances, and both interpretations are reasonable.” Id. (emphasis added). The question of whether an ambiguity exists is one of law, which we review de novo. Id. at 577, 556 A.2d at 83.
*528¶ 27. The language here is clear. With respect to higher assignment pay, the contract states: “[T]he amount paid shall be a differential rate equal to the same rate as the ‘rate on promotion’ in the Salary article. In no case shall it exceed the maximum or be less than the minimum of the pay grade of the higher level position.” The relevant provision of the salary article provides:
[U]pon promotion, upward reallocation, or reassignment of a position to a higher pay grade, an employee covered by this Agreement shall receive a salary increase by being slotted onto that step of the new pay grade which would reflect an increase of at least five percent (5%) over the salary rate prior to promotion (i.e., five percent (5%) is the lowest amount an employee will receive, and the maximum amount would be governed according to placement on a step which might be higher than, but nearest to, the five percent (5%) minimum specified). The rate of five percent (5%) as outlined above shall be 8% if the employee is moving upwards three or more pay grades.
¶ 28. This language plainly expresses the parties’ intent that employees entitled to higher-assignment pay will receive pay equal to the same rate as the rate on promotion in the salary article. The salary article provides that the rate on promotion is the pay rate resulting when the employee is slotted into the step on the new pay grade that results in at least a five percent or eight percent increase over the employee’s prior rate of pay.
¶ 29. The majority finds that employer proffers an equally reasonable construction of this language. According to employer, the phrase “rate on promotion” refers to a five percent or eight percent baseline “rate of increase” applicable upon promotion without slotting into a step on the higher level pay grade. Employer draws a distinction between the “rate on promotion” and the “process” of obtaining that rate upon promotion, and observes that the parties did not specifically state that both the rate and the process should apply in calculating higher-assignment pay. Employer maintains that the words “at least five percent” refer only to the process of promotion itself, and not the “baseline rate” applicable to higher-assignment pay.
¶ 30. The majority agrees that the reference to “rate on promotion” can be reasonably read to refer to a flat five or eight *529percent “rate of increase.” Ante, ¶ 16. It focuses on the reference in the second sentence of the salary article to “[t]he rate of five percent,” or eight percent where applicable, and it appears to credit employer’s assertion that if the parties had intended to provide for the slotting “process” in calculating higher-assignment pay, they would have said so. Ante, ¶ 16. The majority finds its conclusion supported by “the evolution of the agreement,” and the circumstances surrounding the making of the agreement. Ante, ¶¶ 18-19.
¶ 31. The interpretation embraced by the majority finds no support whatsoever in the plain language of the contract. The contract does not distinguish between a “rate on promotion” and the process for achieving that rate, and we should not rewrite the parties’ contract to create such an artificial distinction. The agreement provides for one “rate on promotion” — the rate achieved by slotting an employee into a higher pay grade that reflects an increase of at least five percent over the salary rate prior to promotion, or an increase of at least eight percent if the employee is moving upwards three or more pay grades.
¶ 32. The higher-assignment-pay provision similarly does not refer to a “baseline rate of increase,” nor does the salary article recognize a distinct “baseline rate of increase.” The majority ignores the actual words of the contract in finding that the salary article refers to a “rate of five percent.” In fact, the agreement refers to the “rate of five percent (5%) as outlined above.” The words “as outlined above” directly refer to the slotting process described in the preceding sentence of the salary article. The relevant portion of the salary article is concerned only with the “rate on promotion,” which is a variable rate based on “slotting up.” Five percent (or eight percent) is the “lowest amount” an employee could receive if a step were available at that precise level; otherwise, placement is on the step that is closest to, but not less than, a five percent (or eight percent) increase.
¶ 33. The majority cites “[t]he evolution of the agreement” as support for its conclusion that the disputed language is ambiguous. Ante, ¶ 18. It notes that the reference to the “rate on promotion” provision in the salary article was added to the higher-assignment-pay article at the time that the salary article was revised to include the five and eight percentage increases to be applied to promotional pay calculations. The majority deems it plausible that this “was intended to capture that applicable *530percentage differential in a particular case rate rather than to incorporate the entire process for calculating promotional pay into the higher-assignment-pay article.” Ante, ¶ 18.
¶ 34. I disagree that this evidence shows an ambiguity in the contract. We allow a limited inquiry into the circumstances surrounding the making of an agreement in inquiring into the existence of ambiguity. Isbmndtsen, 150 Vt. at 579, 556 A.2d at 84. For ambiguity to exist, a writing “in and of itself’ must support “a different interpretation from that which appears when it is read in light of the surrounding circumstances,” and both interpretations must be “reasonable.” Id. Nothing in the written language of this contract supports the notion that a flat rate applies to higher-assignment pay, while a different rate applies to promotions. The contract clearly states that the rates are the same.
¶ 35. Rather than supporting the majority’s interpretation, the surrounding circumstances support the enforcement of the language as written. As the dissenting Board member pointed out, the promotional and higher-assignment pay increases were both set at eight percent prior to the contract at issue. The changed language continued the identical treatment by converting straight percentage increases in both cases to the pay rate resulting in at least a five percent or eight percent increase after being slotted into the appropriate step. Thus, the surrounding circumstances in this case show that higher-assignment pay has always been identical to promotional pay increases in past contracts, and the disputed contract language continued this pattern. This view of the surrounding circumstances is consistent with the plain language of the contract; the majority’s approach is not.
¶ 36. I am equally unpersuaded by the majority’s reliance on “the uncontradicted accounts of the circumstances surrounding the making of the agreement from individuals who were on both sides of the bargaining table at the time the higher-assignment-pay language was amended to reference the rate on promotion provision.” Ante, ¶ 19. The State’s or VSEA’s “understanding” of the contract terms, or their lack of discussion about “slotting,” cannot be used to vary the plain language of the parties’ agreement. Their beliefs do not render the contract ambiguous. Our goal in interpreting contracts is “to give effect to the intent of the parties as that intent is expressed in their writing,” and “[w]hen the contract language is clear, the intent of the parties is taken to be *531what the agreement declares.” Hamelin v. Simpson Paper (Vermont) Co., 167 Vt. 17, 19, 702 A.2d 86, 88 (1997). If the parties intended to impose a flat-rate increase for higher-assignment pay, they could and should have said so in the contract. Instead, they drafted language that plainly provides for “slotting up” in calculating higher-assignment pay.
¶ 37. Finally, I am unpersuaded by the Board’s rationale that its interpretation is supported by the past practice of the employer to provide only a five percent increase without slotting in circumstances of higher assignment. Up until this decision, the Board had described the governing law as: “[A] mistaken interpretation by the State of a provision of the Contract cannot justify denying employees rights to which they are entitled under a correct interpretation of the contract. A contractual provision which is incorrectly interpreted for a period of time does not render the provision invalid.” Vermont State Emps. Ass’n, 11 V.L.R.B. 300, 306 (1988); see also Nottingham, 25 V.L.R.B. 185, 192 (2002). The Board has ignored its own precedents in ruling to the contrary here.
¶ 38. “Our duty is to interpret disputed contract language, not remake it, or ignore it.” In re Graves, 147 Vt. 519, 523, 520 A.2d 999, 1001 (1986) (quotation omitted). Because the contract language here is unambiguous, it should be enforced as written. Grievant is entitled to higher-assignment pay of at least five percent after being slotted into the appropriate step, and the majority errs in concluding otherwise.
¶ 39. I am authorized to state that Justice Crawford joins this dissent.