Can i switch sim cards to a different working iphone

Yep! As long as they are the same size of course. You may want to Reset Network Settings after it is done and verify that your carrier has recognized the change. You may have to contact your carrier. The phone will adopt the number of the SIM card switched to it. What would you do with the SIM on the working phone?

You may if you wish - but there are certainly many reasons not to do that.

Remove or switch the SIM card in your iPhone - Apple Support