3 trips.

1 to tear up and reinstall 1 sheet, I would say 2 persons 1hr  tape and mud.

2. sand and second coat of mud. 1 person, 30 min.

3. sand and paint two coats. 2 hours.

The number of minutes or hours on site time does not matter, because any trip will probably carry a charge of the minimum of 4 hours.