Yes, should be something like:
NewString = mid(OldString, (instr(OldString," "))+1, ((Len(OldString))-(instr(OldString," ")))-1) & "," & " left(OldString, (instr(OldString," "))-1)
can be done with less repetition if you want it in code, rather than a single line expression as above.
I should also warn that I'm doing this in my head as I'm posting this from a PC without Access on it, so I can't test it at the mo.
Mike