How can I reuse a Prolog data structure?

How can I reuse a Prolog data structure?

I am writing a small program using Prolog. There is a data structure that
I want to reuse, so I tried assigning it to a variable:
CitizenProfile = voter_profile(citizen,not_in_prison).
Then I used it like this:
state(alabama, [CitizenProfile]).
However, I am encountering this error when I compile my file from the
console:
No permission to modify static_procedure `(=)/2'
I even tried declaring the equal sign dynamic, but that didn't solve
anything. :(
:- dynamic (=)/2.