John makes an offer. jane justifiably relies on that offer to her detriment by beginning performance. john cannot revoke his offer any longer because of:

John cannot revoke his offer any longer because of promissory estoppel. The is an element of the contract law t hat states that a promise is enforceable by law, even if made without formal consideration. The promisor in this case is John and the promisee is Jane. When a promisor has made a promise to a promisee the promise is enforceable by law.