12 C.F.R. § 1005.8

(a) Change in terms notice—(1) Prior notice required. A financial institution shall mail or deliver a written notice to the consumer, at least 21 days before the effective date, of any change in a term or condition required to be disclosed under § 1005.7(b) of this part if the change would result in:

(i) Increased fees for the consumer;

(ii) Increased liability for the consumer;

(iii) Fewer types of available electronic fund transfers; or

(iv) Stricter limitations on the frequency or dollar amount of transfers.

(2) Prior notice exception. A financial institution need not give prior notice if an immediate change in terms or conditions is necessary to maintain or restore the security of an account or an electronic fund transfer system. If the institution makes such a change permanent and disclosure would not jeopardize the security of the account or system, the institution shall notify the consumer in writing on or with the next regularly scheduled periodic statement or within 30 days of making the change permanent.

(b) Error resolution notice. For accounts to or from which electronic fund transfers can be made, a financial institution shall mail or deliver to the consumer, at least once each calendar year, an error resolution notice substantially similar to the model form set forth in appendix A of this part (Model Form A-3). Alternatively, an institution may include an abbreviated notice substantially similar to the model form error resolution notice set forth in appendix A of this part (Model Form A-3), on or with each periodic statement required by § 1005.9(b).