Is retracting a waiver of property permissible? And is completing university studies lawful?

Waiving ownership to another is considered a gift (hibah). If the gift meets its conditions, meaning the giver (wahib) was competent to dispose of the property, and the recipient (mawjoob lah) took full possession of the property before the giver's death or bankruptcy, then the gift is valid, and the giver does not have the right to revoke it. This is based on the Prophet's (peace be upon him) saying: "It is not for us to set a bad example; the one who revokes his gift is like a dog that returns to its vomit." However, if the gift does not meet its conditions, such as if the recipient did not take possession of it, then the giver has the right to revoke it. This is based on Abu Bakr's statement to Aisha (may Allah be pleased with her) regarding her gift: "If you had taken possession of it or acquired it, it would have been yours. But today it is the property of an heir." Therefore, it is permissible to revoke what the giver has waived before the recipient takes possession of it.