Basically, within Drupal I’d wanted to change the order that the hook_form_alter hooks were executed. In order to do this all you need to do is to set the “weight” of the module in question to a greater value. In our example, I wanted my module to execute its code after the location module. The location module has a weight of 0 (the default), so simply be setting mine to 1 its code was executed after the location module’s code.