There are numerous phrases that would do but if you can provide some context then it might be possible to point out one that is most appropos. If he is in sales, you could say he is a "closer" (i.e. one who routinely closes the deal).

If he is a generally competent, independent and reliable chap, and if you were certain that your audience would understand you, you could simply say he is "a man who can take a message to Garcia" (able to get things done regardless of difficulty).

Last edited by Alex Williams; 12/10/2007 6:06 PM.