Mister Ed

Correction: Just because we don't see him actually being told, it doesn't mean that he wasn't informed, off-camera. The moment it became apparent that the Enterprise was being stolen, Starfleet would have been investigating to work out who was responsible - given that Kirk's already asked if he can take the ship, it wouldn't take much to work out who was behind the theft, and they would have informed the Excelsior immediately. Styles would have had the information given to him the moment he reached the bridge.

Tailkinker