If i jailbreak a Iphone 4 thats for at&t, can i use it on Verizon?

I have an old iphone, that i want to give to my friend who has a different carrier, and were just wondering if it would afftect any verizon updates or anything.
>>> If i jailbreak a Iphone 4 thats for at&t, can i use it on Verizon?