In our supplement they are required to give us 24 hours notice on start time changes of one hour or less and 72 hours notice of changes one hour or greater.
Our center manager tried to pull a fast one----he changed our start time to 9:40. Our on-car claimed that he announced it at the PCM but no one recalls it being said.
If they try to start you early without giving you 24 hours notice it is your option whether you want to start early and the time before your posted start time is OT.