Parametrs in Access

I start the same report from several forms. The user limits the report from the form via the criterion in OpenReport. How do I mention the limitation in the report header? I cannot use VB to assign to the header, because one cannot assign to that object. What I am doing is putting the parameters in a module along with functions returning the parameters, and then using those functions in an expression defining the header. This works, but is not handy. I want something neater.