Appointments+ Plugin

Is there any way to change some of the wording in the Appointments+ plugin? I can see that in some cases that's possible via the shortcodes, but not all.

A few things I would like to change are:-
> the "no preference" first option in the app_service_providers drop-down.
> the phrases "Service name" and "Service provider" in the app_confirmation box.

Obviously I can "hack" the code but is there a better way to do this?