According to 12 CFR 226.23, in a credit transaction in which a security interest is or will be retained or acquired in a consumer's principal dwelling, each consumer whose ownership interest is or will be subject to the security interest shall have the right to rescind the transaction, with some exceptions. To exercise the right to rescind, the consumer shall notify the creditor of the rescission by mail, telegram or other means of written communication. Notice is considered given when mailed, when filed for telegraphic transmission or, if sent by other means, when delivered to the creditor's designated place of business. The consumer may exercise the right to rescind until midnight of the third business day following consummation, delivery of the notice required by paragraph (b) of this section, or delivery of all material disclosures, whichever occurs last.