You can get around 3qts +/- a lil on a drain and fill. If you go that route you'll just have to repeat it another time or 2, depending how your fluid looks. That's what I choose to do for mine. It's a simple process just have to make sure not to overfill it. So just have to measure what you get out & put that same amount back in.
The dealer would be the faster option if you don't mind the cost or don't want to do it yourself. I'd make sure what they are actually gona do 1st though, so you don't end up paying for fresh fluid but end up with just a drain & fill.