SU (Resource Kit)

Switch User.

Syntax
      SU  "[cmdline]" [domain] [[Winsta\]Desktop] [options]

Key
   cmdline        The command to run (default =%comspec%)
   domain         The domain for the user account ('.' = local m/c)
   Winsta\Desktop The profile to load (default = current)

Options

  -cb console bypass
  -dn do not switch to new desktop
  -g  GUI option
  -l  load the .Default user registry hive
  -w  use current registry hive 
  -e  Inherit parent environment
  -b  batch logon 
  -i  interactive logon 
  -s  service logon
  -n  network logon
  -v  verbose

All LogOn Types require specific User Rights to be granted...
SeNetworkLogonRight, SeServiceLogonRight, SeInteractiveLogonRight, SeBatchLogonRight

The RUNAS command is a lot easier to use!

“He who reigns within himself, and rules passions, desires, and fears, is more than a king” ~ Milton

Related:

RUNAS - Execute a program under a different user account.
PsExec - Execute process remotely
Powershell: you can run an entire powershell session via RunAs to elevate your permissions.
Equivalent bash command (Linux): su - Run a command with substitute user and group id