I dont belive its possible to swap seats while driving, on most trucks you would have to tip the cab to undo the bolts.
Swapping seats while driving was common practice on long distance non stop international coach journeys with two drivers.
Option one is stop for tacho breaks at night and wake up the passengers, if it is school kids, they will not settle down and make a noise all night.
Option two is keep driving and swap seats and they wake up at their destination.
My Dad saw drivers swap seats in Germany,one holds the wheel, then slide in the seat and swap.
simon1958:
chester1:
fuse:
they are allowed to so long as at least one has one hand on the wheel,nothing will happpen to themFool … Even if they where aloud they will be driving on the wrong card and who is covering the brake
… And what about a blow-out on the front with one hand on the steering wheel?..
Do you ever change gear?
Meh, more accidents that might have happened, but didn’t, Trucknet knickers-in-a-twistery.
Own Account Driver:
simon1958:
chester1:
fuse:
they are allowed to so long as at least one has one hand on the wheel,nothing will happpen to themFool … Even if they where aloud they will be driving on the wrong card and who is covering the brake
… And what about a blow-out on the front with one hand on the steering wheel?..
Do you ever change gear?
Yeah but I usually don’t have to change seats to do it. 
Perhaps they were bored and decided to have a game of “musical chairs” 
swapping like this?
youtu.be/E6VHsqt2GjQ
d2m2s:
swapping like this?
youtu.be/E6VHsqt2GjQ
The music says it all.