Have an issue with dental retainer, can it be fixed in office?

I am just curious about this, my orthodontist will not be open until Monday and I wanted to see if anyone knew whether retainers are made in office, or are sent out to be made somewhere else? I had a "permanent" retainer that had to be removed and the orthodontist made me a new removable one. It is one of the retainers that have wires that go along the front of the teeth and have a plastic mold that fits in the bottom of the mouth. There is a lip on one side of the plastic that juts out farther than the other, and it digs very badly into the gums below one molar. It is so bad, I cannot actually press the retainer into place. It would have to be worn loose and upward on that side. I am wondering if the orthodontist will be able to easily remove that little defect in the office, or if he will have to send it out to have the plastic remolded elsewhere. It is a very tiny line of plastic that needs to be shaved or molded down. I am just hoping it will not have to be sent out, because it will likely take more time, more money, and an extra appt. to get it back, if it is sent out somewhere else. Thanks for any answers!