Depending on the type of schedule your zone is following, setpoint overrides will be treated differently. Below is a quick take on how setpoint overrides will be treated when the zone is following different schedule types.
Building Schedule - Overrides hold until the end of the current occupied period. Then go back to the scheduled setpoints
Zone Schedule - Overrides change the desired temperature for the zone schedule for that day indefinitely.
Named Schedule - Just like building schedule overrides, hold until the end of the current occupied period.