remote doesnt work. need to reenter wifi password.

My apple tv remote hasn't worked in iver a year but i have the remote app on my iphone which works wonderfully. however, i got a new modem and need to reenter the wifi password on my apple tv but i can't do so with the app because the apple tv isn't connected to wifi and they can't talk. how do i pair the remote app on my iphone without wifi or set the password on apple tv without the use of the original remote?