Update Manager Authorization

I was wondering to know how comunicate vCenter and Update Manager with each other.

I have done some research and I have found that there is no special autorization from vCenter to Update Manager.

It just Update Manager keeps some credentials for vCenter and authorization is just in that direction.

Am I right?

So the question is, when I get message like this: "There was an error connecting to VMware vCenter Update Manager - [hostname:443]. vim.fault.InvalidLogin." I should change credentials on Update Manager server.

How can I do that without Update Manager reinstallation?

I don't have Vmwareupdatemanagerutility.exe in "c:\program files\...\update manager" directory.

Regards.