[Hondaracer]

I’d see where the seams are and see if you can pop off the entire piece

Otherwise you’re going to need a multi tool/oscilating saw or somthing like that to cut out a smaller section. If you are able to pull out a entire section cleanly or if you can cut out a smaller piece I’d then bring the piece to Home Depot, or mouldings and mill work in port kells and they should be able to match it up for you.

Then if you don’t have a brad nailer etc. It gets a little trickier..id probably get some smaller finishing nails and use a hammer gently to at least suck the board into the wall at tight as possible then just caulk the edges and holes and touch up with paint. May have to paint a larger section than what you replaced to make it look decent