switch resolution profiles

[_pi]

i have two monitors on my computer and sometimes
i need to disconnect the second screen when administrating
a second computer (booting, recover, ...).
as long there is no access via vnc to this computer i have
to switch my desktop to one screen.

how to manage this by script, so that my original settings
will be restored on reconnect ?

currently i have to open the display cpl and activate the second screen
by hand (sometimes, because of strange xp behaivor even the
frequence - 85 has to be manualy adjusted)

thanks