BS from someone that doesn’t know how to do it/Only the manufacturer can really answer that question properly.
On thing to have it repaired. Another thing to have it tested. And another thing to put in to service….
Like did it get dented and the varnish is scraped?
Or did it fail.?
It depends on the extent of the damage: if it passes standard transformer tests a little epoxy to clean up the damage is all you need.
Rewinding is usually only done on very large or unusual transformers where lead time is an issue. Removing the varnish or epoxy means heating to 550-650 at for several hours to burn it off. You can’t realistically do a small area.