Utah Code § 78B-5-815: Release, settlement, or statement by injured person -- Notice of rescission or disavowal.

Notice of cancellation or notice disavowing a statement, if given by mail, is given when it is deposited in a mailbox, properly addressed with postage prepaid. Notice of cancellation given by the injured person need not take a particular form. It is sufficient if it indicates by any form of written expression the intention of the injured person not to be bound by the settlement agreement, liability release, or disavowed statement.