The revocation is only established through a witness and an oath, as the objective of it is wealth. This is the school of al-Shafi'i. And Allah knows best.

1938 - Issue: He said: (If a house were in his possession, and a man claimed it, and he [the possessor] acknowledged it to be for someone else, then if the one for whom it was acknowledged is present, he is made the adversary regarding it. If he is absent, and the claimant has evidence, judgment is passed regarding it for the claimant based on his evidence, and the absent party remains [liable] for his litigation whenever he arrives.)

Its summary is that if a person claims a house in the possession of another, and the one in whose possession it is says: "It is not mine; it is only for so-and-so." If the one for whom it was acknowledged is present, he is asked about that; if he confirms it, he becomes the adversary regarding it, and he is treated as the possessor. This is because the one in whose possession it was acknowledged that his possession acts on behalf of the other's possession, and a person's acknowledgment regarding what is in his possession is a valid acknowledgment, so he becomes an adversary to the claimant. If the claimant has evidence, judgment is passed in his favor. If he has no evidence, then the statement is that of the defendant [the possessor] along with his oath. If the claimant says: "Make the acknowledger, in whose possession the object was, swear to me that he does not know it belongs to me," he is obligated to take an oath; because if he had acknowledged it for him [after his previous acknowledgment], he would be liable for damages, just as if he said: "This object belongs to Zayd," then said: "It belongs to 'Amr," it is surrendered to Zayd, and he pays the value to 'Amr. Whoever is liable for damages upon acknowledgment is liable for an oath upon denial. If the person for whom the acknowledgment was made rejects it and says: "It is not mine, it is rather for the claimant," judgment is passed in his favor. If he does not say: "It is for the claimant," but says: "It is not mine," then if the claimant has evidence, judgment is passed in his favor, and if he has no evidence, there are two views; one of them is that it is surrendered to the claimant, because