How to record on another sky box?

Okay so in my house there are 2 sky boxes one in my parents room and one in my front room, I also have the sky+ app on my iPhone but every time I set something to remote record it records onto my parents box instead of the box in the front room how can I change it so that it records on the front room box?

The phone line is only connected to one box

The box that records needs 2 cable feeds from the dish. Seems that it is the box in the front room.