They are all different, some you do this way, others you do that way.
What is the control panel?
I expect it would be take cover off detector, tamper sounds, enter your code to silence.
Do your thing, put it back together correctly, enter your code to reset the tamper fault - POSSIBLY.
If the panel is programmed to be engineer reset on tamper you will have a problem.
What's the panel?
acorn
January 2011