C X - we would need a few more details than that.
Do you really mean convert "TO ICAO", if so, what from??
Give us a more specific question - with a few ideas as to what (presumably) "you" already hold - and what, exactly, are you trying to do?
By that, I mean, what kind of job in which country? If you want to keep it (more) confidential then send it to me by e-mail or private message.