Here's a bit of code I stumbled across one time to do the job in Visual Foxpro. It's just API stuff that should be easy enough to convert to dot nyet.

...Art

* If the table "Products" is in a protected folder, for example and the user "ProdAdmin" has rights to the folder, then:
if Impersonate("ProdAdmin", "ProdPassword")
   * I use a mapped drive just as an example, of course it is not needed or desireble
   USE X:\ProductFolder\Products
endif
* Do some process
EndImpersonate()

FUNCTION Impersonate(UserName As String, UserPassword As String) As Boolean
   Declare Integer LogonUser IN advapi32 ;
   	String lpszUsername, ;
   	String lpszDomain, ;
   	String lpszPassword, ;
   	Integer dwLogonType, ;
   	Integer dwLogonProvider, ;
   	Long @phToken
   Declare Integer ImpersonateLoggedOnUser IN WIN32API Long ptr   
   Declare RevertToSelf IN ADVAPI32

   LOCAL nToken, loNet
   nToken = 0
   loNET  = CREATEOBJECT('wscript.Network')
   IF LogonUser(UserName, loNET.UserDomain, UserPassword, 2, 0, @nToken) > 0
      IF ImpersonateLoggedOnUser(nToken) > 0
         CLEAR DLLS
         loNet.MapNetworkDrive('X:', '\\skyapps\apps') && Map all network drives is necessary
         RETURN .t.
      ENDIF
   ENDIF
   CLEAR DLLS
   RETURN .F.
ENDFUNC

FUNCTION EndImpersonate() As Boolean
   Declare RevertToSelf IN ADVAPI32
   RevertToSelf()
   CLEAR DLLS
ENDFUNC