There are two Sonics here with dine in service. I've dined in many times. The dine in has the same ordering requirements. The difference is you go to the counter and order. The photos are the same. The only real difference is you eat in the dining room not in your car.
Right now the dining room at both those locations have closed the dining rooms. Both have a sign on the door that says "Dining Room Closed." I take a photo of the sign (I upload it although I haven't been asked for it) and go to the drive-thru. There's a place on the form that asks if you did the shop differently. Then you follow the drive-thru directions, which are the same except you capture the drive-thru timings.