Most modern cars have plastic bumpers which bend if you bump something, and usually rebound to their original shape, with no harm done except a scuff on the surface paint. If the bump is enough to leave a concave dent, can it be repaired (rather than replaced) and does that need special equipment in a body shop? Ash.
If the “reshaping” is not too severe, you could try a bit of diy - using a hair dryer! At max heat, full blast, played over the dented area, the plastic can be “warmed” (and therefore “softened” …without melting it) enough to make it more pliable.
Enough, perhaps, to get it to ping back to its original shape or respond to push and shove and even pull with (gloved) hands or a suitable implement (e.g. a puller or rubber hammer) to restore it to something very near its original position. Successful or not, “hot” plastic is easier to manipulate and is less likely to crack in the attempt.
If that tactic succeeds, the repair will need little or no “filler” to give it a perfect surface, ready for the final cosmetic of spray paint.
Professional body shops will of course have much more experience, specialised tooling and finishing options than the average amateur, but motorists with some basic tools and mechanical ingenuity will be able to emulate some of those techniques.
