So that the Community can help you better, we will need to know exactly which operating system is running on your computer. That, and any other details you'd like to give will only help the Community better understand your issue!
It is easy to do, if not a little wasteful. Just select 11 x 17 or 13 x 19 paper size in the page set up. Then Light Room, or PS, will let you specify 11 x 14. You will need to trim the paper after it is printed.