I issued you expect vectors for 34L in Seattle to which you happily agreed. Seattle had a line of aircraft waiting for takeoff on 34R nod I had another aircraft inbound 34C. Upon clearing you for the ILS 34L you start turning 90 degrees to the right away from 34L and request frequency change. I recreated you for the 34L approach with a new heading and altitude to get you back on course. You decided you were smarter than approach and switched frequencies without permission thinking you could ask Tower for 34R
Instructions when given an ILS approach are not voluntarily handed out they’re handed out for traffic congestion me to keep order in the airspace. Deciding you are going rogue will get you a violation. Next time please follow instructions!