Verizon Sim Card! i need help please!?

Okay i have a htc thunderbolt which is activated under my account and i will be trading it for my friends droid charge which is under his account. So my question is, to make the trade is all i have to do is take my sim card from my htc thunderbolt and put it in his droid charge and it will automatically activate to my account? Same with him instering his SIM card into my htc thunderbolt. HELP PLEASE! THANK YOU AHEAD OF TIME!