[officialtony]

I assume you are talking about a soccer referee even though you posted on a wrestling forum. I would go right to the official and ask him how he felt about the call you are questioning. Also ask him what association he belongs to. Then ask him if he would be willing to consider another approach to the call you are questioning. If he is, tell him. If he isn't, don't.
You can go to his association ( they are all listed on the state website ) and share your opinion with them.
There is a good chance he already knows he booted one ( if, in fact he did ). There is also a good chance he feels very good about the call he made. And a good chance it may have been the right one. I don't know where you were or why you are so sure it was a " poor call ", but most officials know if they have booted one and probably feel worse about it than anyone else involved. If it was only ONE call you found " poor ", I'm not sure if pointing it out to him, or anyone else, is needed. We all miss one once in a while. We all see 'em differrently at times too. I wouldn't be too quick to judge.
Just one officials opinion.