Hi.
What kind of an instrument You're talking about? Price- and value-wise.
For a cheapo, a quick fix attempt would be to remove the strings and loosen the truss rod completely. Bending, twisting and eyeing of the neck will then tell whether the problem can be corrected or not.
For an expensive instrument, the frets are removed (if any

), the fret-/fingerboard is leveled and then refretted.
The first scenario will set You back whatever a full setup is worth in your local shop + strings obviously.
The second one may cost a refret + an extra hour or two of labour + setup.
Regards
Sam