Once the data on the disk is encrypted, the key associated with the encrypted data has to be changed for security reasons. The change policy is organization specific. The process of changing the key associated with the encrypted data for a disk from an old key to a new key is referred to as the rekey process.
Rekeying is a special function of the data preparation operation where the currently encrypted contents of the disk is read, decrypted using the current (old) key, encrypted with a new key, and written back to the disk.
Note You cannot change the quorum or the master node during a Master key rekey.