String Substitution?

I need to call a procedure called "Enableall" from my VBA code in the form. This function is defined as follows:

Sub enableall(bolenable as boolean, frm as Form)

When I call this using the following method it works fine:

enableall false, me

However, if I need to substitute a variable, say, var=forms!myform and then I call this function the following way it doesnt work:

enableall false, var


What is the correct syntax to call this procedure? I run into this string substitution problem all the time....Is there an easy way to remember how number / string variable substitution works in Access?

Thanks.