5 C.F.R. § 511.602
An employee whose position is reclassified to a lower grade which is based in whole or in part on a classification decision is entitled to a prompt written notice from the agency. This includes employees who are eligible for retained grade or pay. If the reclassification is due to an Office classification certificate issued under the authority of 5 U.S.C. 5110, the agency will also explain the reasons for the reclassification action to the employee. This notice shall inform the employee: