hi, i'm assuming you want to pick up at apple store? if so, yes, but theoretically you need to be 'authorized on the account' in order to pick it up. i don't know if they actually check. it's easy to add you online. your friend will get hit with a $30 upgrade fee on the next bill. no idea if it affects their future upgrades.
their number will NOT be transferred to the new phone if you don't activate in store. when you pick up the phone, don't turn it on. take the phone home, and BEFORE you turn it on, take out the included SIM card and put yours in. that should work.*
*disclaimer: i did this, successfully, with an AT&T SIM using a verizon phone. i don't know if there are any potential pitfalls going from verizon to verizon.