We moved the garage door from 1 side of the garage to the adjacent side (so the door is now 90 degrees from its original location). Now the garage door does not close completely, because the concrete floor is 2 inches higher on 1 side than the other.

Could we find a contractor to grind and taper down the higher side? (We'd hate to have to re-pour the entire garage).

Most equipment rental places will have something you can use to grind or mill the concrete.