Short answer. You may be able to withdraw or amend it. Section 4 gives the court discretion to allow a party to withdraw or amend an admission made under this Rule — whether express or implied — on whatever terms the court considers just.
What the law says
The court may allow the party making an admission under this Rule, whether express or implied, to withdraw or amend it upon such terms as may be just.
Rule 26, Section 4 — Withdrawal. Read the full provision →
The court's discretion
Withdrawal or amendment of an admission is never automatic — Section 4 requires the court's permission, granted only on terms the court itself considers just under the circumstances of the case. A party who wants to change position cannot simply file a notice and treat the earlier admission as erased; a motion has to be brought, and the court decides whether to allow it at all. Because the provision speaks of terms 'as may be just,' the court can condition permission on protecting the other side's reasonable reliance — for example, requiring the withdrawing party to reimburse costs the opposing side incurred in preparing its case on the assumption the admitted fact was already settled. If the court declines to allow withdrawal, the original admission stands and continues to bind the party for the rest of the proceeding, including at trial.
Covers implied admissions too
Section 4's reach is not limited to admissions a party affirmatively put in writing; it expressly covers admissions 'whether express or implied.' The most common implied admission arises when a party fails to respond to a request for admission within the time allowed, so the matters requested are deemed admitted by operation of the Rule rather than by anything the party actually signed. A party caught by that default is not automatically stuck with the deemed admission for the rest of the case — Section 4 gives the court the same room to allow withdrawal on just terms whether the admission came from a written response or simply from silence. Until the court grants relief, though, an implied admission carries the same binding weight as an express one and can be used against the party at trial.
Why courts allow this
Admissions can result from simple haste, an honest misunderstanding of the request, or facts the party only discovered later, after the deadline to respond had already passed. Giving the court flexibility to permit correction avoids locking a party into a factual position that later turns out to be wrong, while still requiring court oversight before anything already admitted can be undone. This balances two competing interests: accurate fact-finding at trial, which suffers if the case proceeds on a mistaken premise, against the opposing party's legitimate reliance on admissions already made in the course of the proceedings. Neither interest automatically wins — the court weighs both before deciding whether withdrawal or amendment serves the merits of the case.