Your own voice is something that should be celebrated and it is possible to be as clear in whichever accent you habitually speak.
Changing your everyday accent to the extent where you can speak another set of sounds without being overly self-aware is a herculean task which takes daily practice and regular classes over a fair period of time.
That said, it is certainly possible to learn another accent for professional purposes. There are many British actors, such as David Tennant, who can switch effortlessly between his native Scottish accent and Received Pronunciation (aka Standard British) with barely a thought. His everyday accent remains joyously Scottish and his own.
As Ben travels more than somewhat, it is unlikely that he would be able to work with a client on the regular basis that this work requires in order to be successful. He cannot, therefore, take on clients who wish to work on Accent Reduction/Modification/Elimination.