It’s not possible for an already-running process to be elevated (or, as far as I know, restricted further). It can be faked by having an already-running process spawn a new elevated process and then communicate with that new process but that only works if you control the code of the program that you wish to have run in a restricted context most o the time but perform some elevated operations.
1
solved How do I elevate privileges of a process running on Windows? [closed]