If the end user is restricted, I mean not a fully elevated user, and the UAC is ON for that machine, then the normal applet is also restricted to the end user's rights. In this case the technician may service the customer but under certain limitations. That's why the TC informs the technician about the UAC, and the restricted state of the end user. This is for the security of the end user to prevent unwanted hacking.
To have "Full" access to the end user's machine the applet should be switched to Windows System Service mode. The technician may switch the applet to WSS during a rescue session when he needs extra functions, like changing users on the machine, access folders that the end user cannot, etc. In this case, depending on the local policy settings either the Tech has to enter the admin credentials, or the end user at the UAC prompt.
It is also possible to initiate WSS mode before session starts. In the admin center there is an option that the applet should start as WSS. When an applet starts on the machine of a restricted user, that option tells the applet to switch to WSS. The applet tries to elevate to have admin rights, it happens before the applet and the TC are connected. This depends on the end user if he has the rights, or the knowledge to elevate. Like if the end user is an admin but not fully elevated, then the policy may let him elevate to full admin with a simple click on the UAC prompt. If the end user is a restricted user, then they have to enter the admin credentials to elevate.
All this occurs before the TC connection. If the end user's elevation fails then the applet falls back to normal/restricted mode.
Hope this helps!
