Its un doing bolts, and then re-tightening them. Even if you factor a haynes manual into the price its still worth it.. I know its not a 'beginners' job, but its not like you'd leave things loose, upside down, wheel inside out, bolts missing then go and thrash it.. If you've done it or seen it done, its not hard, just a bit laborious taking it all apart. I wouldn't advise a child to attempt it, but an adult who's maybe tinkered before, give it a go, be methodical, check everything twice, even 3 times over, from when you slide the jack under right until you lower it back down and re tighten wheel bolts. Or get a much better quote then save yourself the aggro if you're really not up for it?