Is it sufficient for a husband to tell his divorced wife, "Come back," for them to reconcile, given that her waiting period has ended and he intends to take her back as a wife, or is a new marriage contract required?

Revocation is valid with any utterance that could imply it if the husband intends to revoke, such as his saying: "You are with me as you were." He would be asked about his intention behind this utterance. Also, revocation occurs with the intention accompanying the plausible statement. The fact that the used formula is an imperative does not prevent its suitability for revocation, as some scholars have maintained that marriage can be contracted with an imperative formula. Accordingly, the husband's saying "Come" is an expression that could imply revocation or something else. If he intended revocation by it, then the revocation is valid as long as he uttered the phrase within the waiting period (iddah).