I'm trying to explain (for a business law class paper) whether or not this withdraw of acceptance of an offer is effective. I'm going back and forth with it, and I can't come to a solid conclusion. Ernie was fired by his employer, Stein's Sweat Shop. After he was fired, Ernie received a letter from the shop offering him double severance pay in exchange for a release of all age discrimination claims against the company. Ernie signed the release and put it in a mailbox outside the post office. Later, Ernie changed his mind and called the shop to say "I refuse your offer and will be filing suit for age discrimination." Is Ernie's withdraw of his acceptance of the shop's offer effective? Why or why not?