Insert Function with Macro

Hi lonesoac0,
try it

Sub ttt()
Dim x, i&, sp
With Range("A1", Cells(Rows.Count, 1).End(xlUp))
    x = .Value
    For i = 1 To UBound(x)
        sp = Split(Replace(x(i, 1), ",", ""))
        x(i, 1) = sp(1) & ", " & sp(0)
    Next i
    .Value = x
End With
End Sub

I ran the code you gave me and I got the error code of: "Run-time error '13' Type Mismatch". I ran the debugger and it highlighted: "For i = 1 To UBound(x)"

Ok, so I decided to play with it a little more and I inserted two FirstName LastName and it worked just fine. Gracias.