Unjailbreak your iphone

How do i unjailbreak my iphone? I have to send it in for rep and i wont get a new one if its jailbroken

You can plug your phone into iTunes and restore the OS, this will set it back to factory defaults & remove the Jailbreak.

Yes restoring the OS is the only option I guess. I don't know if resetting option will work like the same. But yes restoring via itnues will definitely remove it.

Remember, google is your friend.
Do a fac reset on itunes.