[AccessD] Sending parameters to a query

Hello Group!!!
 
I am at a client site and I am having a brain dead moment here.
 
I have a form where the user selects the parameters for a report (query).  I send the Parameter to the query to populate the report.  Here is the problem, what do I send as the parameter if the user wants to select 'ALL' of the possible values for the Parameter.  I know that I have seen or done this before, but I can not think of how I did this.
 
Please Help!!
 
TIA
 
Jeff Barrows
MCP, MCAD, MCSD
 
Outbak Technologies, LLC
Racine, WI
jeff at outbaktech.com