Running a program as different user is one of the easiest way to impersonate a Program/Application with some other user's privilege. For every administrators, this would be common need either for testing or to impersonate different user privilege.
Run as different user via Commandline:You can run a program under a different user account by using the command line tool RunAs. Use the below command to open new CMD window under different user account.
RunAs /user:TestDomain\Smith CMD