How to wake up WACOM 32 to switch graphics card?

I have a Cintiq 32 Pro, with HDMI and DisplayPort connected to two different computers. If I have finished work on computer A and switch it off, then switch on computer B, the tablet does not wake up automatically and does not switch to the other computer. It also does not react to the touch buttons which I would normally use to select another screen. Is there any way of waking up the tablet/ activating the button without switching the tablet off and on again?