Yes - all the time!
Bit tricky though. I use a long, fine, screwdriver (flathead, i think) inserted through the hole in the underframe near the ends of the coaches. Now you hold the coach so you can see where the screwdriver is going (may have to tilt/angle it and get the light at the correct angle) so you can look through one of windows (door window?) and see the screw holding the roof on. Insert the 'driver so it engages with the screw and press hard and turn. Hopefully the screw will loosen!
Once the roof is off it can be re-attached the same way in reverse - but don't tighten the screw too much!
The first is the hardest!
good luck!
Andrew