How do I dynamically change a list on a CreateView

I want to change the list of status on the Case create view based on a selection made from a drop down list and the role of a user.  I currently have code running which should do this. It will successfully fire when the form is initiated but it does not fire when the triggering field is changed.  I want to change the status list each time the et_case_type field is changed.

initialize: function (options) {

        this._super("initialize", [options]);

        //this.checkRole();

       

        this.model.on('change:et_case_type',this.checkRole(), this);

},

    checkRole: function() {

        var self = this;

  

        app.api.call('read', app.api.buildURL('Users/check_role_membership/' + encodeURIComponent('Archive Cases')),

            null,

            {

                success: function(res) {

                    if (res.isEnabledRole && !res.isAdmin) {

                        var case_statuses = app.lang.getAppListStrings('case_status_dom');

                        var isFCST = app.user.get('roles').indexOf("Fleet Customer Services");

                        var isMobile = false;

                        if(self.model.get('et_case_type') == 1 || !self.model.get('et_case_type'))

                        {

                            isMobile = true;

                        };

                        if(isFCST != -1 && isMobile != true)

                        {

                            delete case_statuses['Closed_for_Customer'];

                            delete case_statuses['Closed_for_Ops'];

                            delete case_statuses['Closed_for_Kwikfit'];

                        }

                       

                        delete case_statuses['Closed_for_Kwikfit'];

                        self.model.fields['status'].options = case_statuses;

                        self.render();

                    }

                   

                },

                error: function(error) {}

            }

        )

    },