Change resolution on Mac-Mini

My mac mini is connected to my TV.
I changed the resolution of my mac mini to a higher resolution and now the image on the tv is running all the time making it impossible for me to use the mouse to change the resolution back.

How do I change the resolution using keyboard only?
Or how do I start my mac mini in a way that will bring it back with a lower resolution?

Thanks

I don't know any shortcuts for changing the resolution, but you could configure your mac to not use a mouse, but using a keyboard only. Well, in the System Prefs, then Universal Access, then Mouse, and click Yes for Mouse keys, then you could activate the keyboard's numeric to be your mouse.

just restart