[Closed] How easy to re-drill rack mount in frame?

One of the rack mounts in my tricross is a bit dodgy, the threads haven't been right since day one, rounded out at the top and it took ages to seat the screw for the rack.

What is the process called where you get threads repaired - chasing? Is it a simple job that all LBSs can take care of?

I'm just off for a week's holiday and want the rack on for carrying the wee man's child seat, and off for serious riding. Got a feeling that constantly swapping it round will finish the mounting hole off.