[AccessD] Splitting up names

If got a user running a db in Access. She has a list of names and they
were all input into a single "name" field, rather than "last name" &
"first name." She would now like to split these names up, but there are
some double first names, as well as "jr" and "sr" suffixes. 

Is there a way to do this?

Basically names might be like this:

JOHN SMITH JR
MARY ELLEN SMITH
BARBARA SMITH

And I'd need to get them like this into a first name field like:

JOHN
MARY ELLEN
BARBARA

and a last name field like:

SMITH JR
SMITH
SMITH

John W. Clark
Computer Programmer
Niagara County
Central Data Processing