The more important general issue in my view is: what really happens to the changed information passed on to Centre/Flightwatch?
Scenario:
Weekend Warrior puts in a domestic notification of a VFR flight A to B to C to D, with a SARTIME of 110730 for arrival at D.
At 110330 WW calls Centre/Flightwatch to advise that she’s at B and intend to divert, at C, to Q via F, and nominates a SARTIME of 110745 for arrival at Q.
Who does what with that information, and when?