Excel XP on WinXP

Inherited a spreadsheet from another user. Have a mixture of lname, fname
and fname lname combinations. I can successfully convert the lname, fname to
fname lname, teh problem is those cells that are already in the fname lname
return a #Value error.

I thought I could find a way to logically test the string for a comma(,) and
use an If statement to control my concatenate formula. I can't find a way to
test logically for the comma.

Can anyone offer a solution?

Thank you