If you're interested in controlling in North America but you are in another divison (not XA) then a GCA is the perfect oportunity.
As a GCA holder (per IVAO Rules and Regulations 5.1.7) you can control in several divisons.
There are some requirements to get a GCA, the most important point is that you must hold the ADC rating. You can find more information here:View PDF
Send an one single email to current Div HQ, XA div HQ and Membership Department with a short reason why you want to switch.
(Example: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org)