The possible synchronization statuses are:
For instance, on account of the fact that the Active SMS has undergone changes since the previous synchronization (objects have been edited, or the Security Policy has been newly installed), the information on the Standby SMS is lagging.
For instance, in the above figure, if a system administrators logs into Security Management server B before it has been synchronized with the Security Management server A, the status of the Security Management server A is Advanced, since it contains more up-to-date information which the former does not have.
In this case, manual synchronization must be initiated by the system administrator by changing the Active SMS to a Standby SMS. Perform a synch me operation from the more advanced server to the Standby SMS. Change the Standby SMS to the Active SMS.

Reference: http://dl3.checkpoint.com/paid/88/88e25b652f62aa6f59dc955e34f98d5c/CP_R80.10_ReleaseNotes.pdf?HashKey=1538443232_ff63052c2c5a68c42c47eae9e15273c8&xtn=.pdf