Changing outgoing bstaff to new staff and associating their clients and candidates to new staff

Changing outgoing bstaff to new staff and associating their clients and candidates to new staff

I want to change Beth Reardon names and associated clients and candidates to to Josh Holland and then delete her. I want to change Nicole Bland names and associated clients and candidates to to Amie Greensted and then delete her. How do I do that. That way we keep the same amount of users.