If you are referring to deposit accounts.
1030.5 Subsequent disclosures.
(a) Change in terms. (1) Advance notice required. A depository institution shall give advance notice to affected consumers of any change in a term required to be disclosed under Sec. 1030.4(b) of this part if the change may reduce the annual percentage yield or adversely affect the consumer. The notice shall include the effective date of the change. The notice shall be mailed or delivered at least 30 calendar days before the effective date of the change.