Is it permissible for the donor to replace the gift after it has been received if he claims error, and does the ruling differ if the contract was a sales contract?

A gift requires the donor's free will and consent. If the donor is prompted to utter the words of the gift without knowing their meaning, or is coerced into it, the gift is invalid. If the donor makes a mistake in the gift and gifts something other than what was intended, some scholars believe they have the right to revoke the gift and substitute it with what was intended, provided there is evidence of their mistake, while others do not permit reclamation.