If the room is actually not longer available, you can inform the guests that the room has only been rented up to a certain point in time and should now be vacated.
However, if the room would still be available and this is okay for you, you can let the guest continue to use the room. You can then contact Workspace2go so that we can adjust the booking and charge the guest for the additional hours.
Tip: Communication is also the most important thing here. Inform the guest that the additional hours will be billed by us. The whole process is then comprehensible for him/her.