Assuming the bolts are only into one plane (wall or floor) you would open the safe, unscrew the nuts, remove the safe from the wall, then deal with the bolts or "studs". The latter would be screwed into the wall and you would unscrew them with a switcble wrench or pliers.

There is probably a section of the stud next to the wall where there are no threads or the threads are not used. The best pliers would be locking pliers like Vise-Grips. Maybe channel locks would work.

I suppose that maybe the studs are special and have wrenching flats and so a regular wrench could be used.

Assuming the bolts are only into one plane (wall or floor) you would open the safe, unscrew the nuts, remove the safe from the wall, then deal with the bolts or "studs". The latter would be screwed into the wall and you would unscrew them with a pipe wrench or with pliers.

There is probably a section of the stud next to the wall where there are no threads or the threads are not used. The best pliers would be locking pliers like Vise-Grips. Maybe channel locks would work.

If the studs would be special design with have wrenching flats exposed when the safe was removed, then a regular wrench could be used.