Karen Ferry (Claimant) appeals an order of the Unemployment Compensation Board of Review (Board) reversing a referee’s decision and denying Claimant’s petition for unemployment compensation benefits pursuant to Section *618402(d) of the Unemployment Compensation Law (Law)1 (unemployment due to a labor dispute other than a lockout).
Claimant was employed by Turkeyfoot Valley Area School District (District) as a teacher and was represented by the Turkeyfoot Valley Education Association (Union) for collective bargaining purposes. A labor agreement between Union and District expired at midnight on August 31, 1987, without the parties having agreed on a successor contract. The teachers continued to work under the terms of the old contract from August 31, 1987 through January 4, 1988. On January 5, 1988, the teachers engaged in a strike which ended on March 10, 1988. The teachers returned to work under the terms and conditions of the expired contract with the additional agreement that 72 hours of written notice would be given before any future work stoppage.
On March 26, 1988, Union gave District notice of its intent to strike on or after March 29, 1988. On March 30, 1988, Union engaged in a strike. That same day, Union offered to return to work on March 31, 1988, under the terms and conditions of the expired contract on a day-to-day basis. District rejected this offer. The teachers reported to work on March 31, 1988, but were not permitted entrance. On April 14, 1988, Union again offered to return to work under the terms of the expired contract on a day-today basis. District rejected the offer. Union’s offers did not include the additional agreement that 72 hours of written notice would be given before any future work stoppage.
Claimant filed a petition for unemployment compensation benefits for the period after March 30, 1988. The Office of Employment Security (OES) granted benefits. District appealed to the referee who affirmed. District appealed to the Board which reversed the referee and denied Claimant benefits.
On appeal to this court, Claimant contends that Union’s offers to return to work under the terms and conditions of *619the expired contract converted the strike into a lockout. Our scope of review is limited to a determination of whether findings of fact are supported by substantial evidence, errors of law have been committed or constitutional rights violated. Avco Corporation v. Unemployment Compensation Board of Review, 105 Pa.Commonwealth Ct. 316, 524 A.2d 531 (1987).
The test to determine who should bear the responsibility for a work stoppage, set forth in Vrotney Unemployment Compensation Case, 400 Pa. 440, 163 A.2d 91 (1960), was summarized by our supreme court in Philco Corporation v. Unemployment Compensation Board of Review, 430 Pa. 101, 242 A.2d 454 (1968) as follows:
[L]ogically the test of whether a work stoppage resulted from a strike or a lockout requires us to determine which side, union or management, first refused to continue operations under the status quo after the contract had technically expired, but while negotiations were continuing.
Id., 430 Pa. at 103, 242 A.2d at 455. However, a strike, once established, may be converted to a lockout. Avco. “[W]hen, as here, the work stoppage takes the form of a strike, the burden is upon the union to show that it made the initial ‘peace’ move by offering to continue the status quo.” Philco, 430 Pa. at 104, 242 A.2d at 456 (Emphasis in original). We must consider the cause of the unemployment on a week-by-week basis. High v. Unemployment Compensation Board of Review, 505 Pa. 379, 479 A.2d 967 (1984).
It is not disputed that the work stoppage on March 30, 1988 was the result of a strike. Claimant contends that the strike was transformed into a lockout when District rejected Union’s offer on March 30, 1988 to return to work the following day under the terms and conditions of the expired contract on a day-to-day basis. Claimant contends that Union offered to return the parties to the status quo. Claimant argues that the status quo is always the terms of *620the expired contract regardless of any subsequent agreements between Union and District.
“The status quo has been defined as the last actual, peaceable and lawful, non-contested status which preceded the controversy.” Miceli v. Unemployment Compensation Board of Review, 519 Pa. 515, 521, 549 A.2d 113, 116 (1988), citing Fairview School District v. Unemployment Compensation Board of Review, 499 Pa. 539, 544, 454 A.2d 517, 520 (1982). Although neither of the parties may unilaterally alter the status quo, the parties may agree to alter the terms and conditions of employment pending the outcome of negotiations. See Local 730 v. Unemployment Compensation Board of Review, 505 Pa. 480, 480 A.2d 1000 (1984). Consequently, we must look to the status of the parties just prior to the March 30, 1988 work stoppage.
It is undisputed that Union and District agreed, prior to the March 30, 1988 work stoppage, that a 72 hour written notice would be given prior to any future work stoppage. The mutually agreed upon notice provision became part of the terms and conditions of employment creating a new status quo. Consequently, Union’s subsequent offers to return to work were required to contain this term. Because Union failed to include this term in its offers to return to work, Union failed to offer to return to work under the status quo and the work stoppage continued to be the result of a strike.
Accordingly, the order of the Board is affirmed.
ORDER
AND NOW, July 2, 1990 the order of the Unemployment Compensation Board of Review in the above-captioned matter is affirmed.
CRUMLISH, Jr., former President Judge, did not participate in the decision.. Act of December 5, 1936, Second Ex. Sess., P.L. (1937) 2897, as amended, 43 P.S. § 802(d).