How can I get a new Exchange code added?

Imported from previous forum

I have already added a new Exchange code to MIC code list. But, I understand that the “Reuters” Exchange codes are still in use. Without knowing if all the Buy side firms have started using MIC codes, I am assuming that it would be safe to add a “Reuters” Exchange code too.
My question is, how do I go about getting this added? Who should I contact?