Advice on teaching a parrot to unlearn a word

I’ve had my parrot for a while now but recently my son thought it would be a funny prank to teach the parrot the N word and now he keeps saying it.

I was beyond upset, that word is abhorrent and I don’t know what I will do if I can’t make him stop saying it, I’m afraid to have anyone over to the house.

Any tips on how to resolve this?