I paid more than half for my galaxy S8 can I upgrade to a different for like a iPhone 6 or 7

[AC Question]

The guy I talked to had said I can upgrade after certain amount of days since I paid more than half of my Samsung galaxy S8 off and I've been wanting to get an iPhone 6plus or 7 instead and just pay off whatever iPhone I get is worth can i do that or no ?

 

[Laura Knotek]

Welcome to Android Central.

What carrier do you have?