Anyway, here are the steps: Go to the passport and immigration office located at Gharrafa. Ask anyone there for typist shops. Go to anyone of them and tell them you want to cancel your wife's RP. They will fill out a form in Arabic. They will put your and your wife's wife's QID number on the form. Once completed you sign the form and pay them QR 10. You then go to the immigration office and go to gate #2. Take your coupon and wait for your turn. When your turn comes, submit the cancellation document and your wife's RP will get cancelled immediately. You will need to pay QR 20 through your ATM for this service. Please note once the RP is cancelled, your wife needs to leave Qatar within 7 days.
Trust this is helpful.