This dispute involves deciding custody of Robin Shifflet, born November 18, 1981, between Robin’s mother, Ginger Shif-flet, and her paternal grandmother, Ortha Shifflet. The trial court awarded custody to the grandmother, using the “best interests of the child” standard. The Court of Appeals reversed with directions to enter judgment for the mother, citing law “that in a custody dispute between a parent and a non-parent, the parent will prevail unless it is shown by clear and convincing evidence that the parent is unfit.” For reasons to be stated, we reverse the decision of the Court of Appeals, but we do not reinstate the decree. We remand to the trial court to retry the custody *393issue. The principles that control deciding the issue between the parties are set out in a similar case, Greathouse v. Shreve, 891 S.W.2d 387, which will have the same rendition date as this opinion.
As stated, Robin Shifflet was born in 1981 to appellee, Ginger Carol Shifflet, and to Robert Shifflet, the son of appellant, Ortha Shifflet. The trial court’s “Order” recites:
“Although there is some dispute among the parties concerning when Robin was delivered into the custody of Ortha, the facts show that since Robin was a baby she has spent the vast majority of her life in the custody of Ortha. After her birth in November of 1981, Ortha took Robin into her home along with Ginger’s other children when Ginger was incarcerated in April of 1982 for shoplifting. This began a long series of incarcerations which predominated in Ginger’s life until 1989....
The evidence is also compelling that since 1989, Ginger has ‘changed her life’. She now lives with a man named Richard Peck who is by all accounts a law-abiding, steadily employed, responsible person. She and Richard Peck live now in Danville, Illinois, where Ginger is also employed at a nursing home. They live with Ginger’s daughter from a prior relationship and Mr. Peck’s son from another marriage.”
The trial court’s Order further reflects that the father, Robert, “has a long criminal history including allegations of sexual abuse of a child.” He is not a party seeking custody in this case, and “Ortha testified that she does not allow Robin to visit with her father overnight,” although the record further reflects that a social worker, Gail Combs, reported that Robin had spent the weekend with her father in the recent past and reported unsupervised visits. It should be noted that Ortha, while found appropriate to the award of custody, has in the past pled guilty to shoplifting, and has a daughter who may be involved in the care of the child who has, in the past, been arrested on multiple occasions for shoplifting and alcohol intoxication. Although the trial court awarded custody to Ortha, the paternal grandmother, and there is ample evidence to support the trial court’s finding that such award was in the best interest of the child, primarily because the child appeared to have been well taken care of in Ortha’s home for almost ten years at the time of trial, custody with the 61-year old grandmother is arguably less than an ideal situation.
The trial court rested its authority to use the best interests of the child standard in KRS 403.340(2) in deciding custody, rather than recognizing the superior right of the parent (KRS 405.020), on the fact that when Ginger and Robert were divorced in 1985, by agreement the decree of dissolution granted “temporary custody of Robin ... to Ortha Shifflet, the mother of Robert.” The trial court stated KRS 403.340(2) “defines the standards to be apply when a modification of a decree concerning a custody order is to be considered.” The Court of Appeals is entirely correct that “the trial court erred as a matter of law in its application of KRS 403.340(2).” The Court of Appeals stated, and we agree:
“Clearly the standards set forth in this statute are intended to apply only to modifications of permanent awards of custody.”
Further, and no doubt because these standards apply only to modification of a permanent custody decree, KRS 403.340 does not simply apply a “best interests of the child” standard; it specifies doing so only upon proof “the child’s present environment may endanger seriously his physical, mental, moral or emotional health” (KRS 403.340(1)), or proof “the custodian agrees to the modification” (KRS 403.340(2)(a)), or proof “the child has been integrated into the family of the petitioner with the consent of the custodian” (KRS 403.340(2)(b)). None of the preconditions to modifying a custody decree “to serve the best interests of the child,” 'as stated in KRS 403.340, apply here. The “best interests of the child” standard is set out in KRS 403.270, and applies to a custody dispute between parents: “the court shall determine custody in accordance with the best interests of the child and equal consideration shall be given to each parent.”
However, although we agree with the Court of Appeals that the trial court erred in applying the law to this case, nevertheless we *394reverse and remand the Court of Appeals because we are in partial agreement with the dissenting opinion of Judge Emberton. Judge Emberton opines that “under certain circumstances, the parent should be estopped from asserting her superior right to custody.” Judge Emberton characterizes the principle at work as “equitable estoppel,” and states:
“When a parent relinquishes control of a child to a non-parent, the care and support furnished may be for such a length of time and under such circumstances as to estop the parent from denying that she has forfeited her natural right to custody of the child.”
We do not agree that the principle at work here is one of estoppel, but we do agree that there is a closely related principle that must be considered. The evidence raises a question of waiver: did the actions of Ginger Shifflet amount to an intentional and voluntary waiver of her superior right as a pai-ent to the custody of her child, Robin? If so, the trial court would be justified in applying the best interests of the child standard in deciding custody between Ginger and Ortha, the paternal grandmother. As we state in Greathouse v. Shreve, supra:
“Waiver differs from estoppel primarily because it does not require proof of the other party having been misled. Waiver is essentially unilateral, resulting as a legal consequence from some act or conduct of [the] party against whom it operates, and no act of [the] party in whose favor it is made is necessary to complete it.’” See Greathouse, at 390 (citations omitted).
Further, as we stated in Greathouse:
“What evidence constitutes proof a parent, who is not proved unsuited to the trust (KRS 405.020(1)), has waived his or her superior custodial right when that right is challenged by a non-parent? As we stated above, waiver requires proof of a ‘knowing and voluntary surrender or relinquishment of a known right.’ Because this is a right with both constitutional and statutory underpinnings, proof of waiver must be clear and convincing. As such, while no formal or written waiver is required, statements and supporting circumstances must be equivalent to an express waiver to meet the burden of proof.” Id., at 391.
The parent’s superior right of custody is not lost to a non-parent, including a grandparent, simply because a child is left in the care of the non-parent for a considerable length of time. As we state in Greathouse:
“Thus, the first question here is whether, considering the totality of the evidence, [the parent] engaged in a knowing and voluntary relinquishment of [her] superior right of custody, to which [she] was entitled unless unsuited to the trust. If [she] did so, the next question here is whether, in present circumstances, [the parent] or [grandparent] should be awarded custody in the best interests of the child.” Id., at 391.
Thus we reverse the Court of Appeals’ decision without affirming the trial court’s decree. We remand this case to the trial court for further consideration and decision consistent with this opinion.
STEPHENS, C.J., and LAMBERT, REYNOLDS and STUMBO, JJ., concur. SPAIN, J., concurs by separate opinion in which WINTERSHEIMER, J., joins.