How can I convert a list of Active Directory Display Names in User Names?

I have a list of Display Names that need to be converted to Active Directory User Names.  The list is in a CSV format and looks like this:

"White, Charles"
"Henry, Marcus"
"Farrior, Anthony"
"Basis, Ian"
"Heenan, Michael"
"Anderson, Anthony"

I can open in Excel and convert to almost any format.  I was thinking maybe PowerShell or something like that but am willing to use anything.

Thanks in advance.