any though here ...type mismatch on date.

For Each rep In Rng1.Cells   '-> this is from...   Set Rng1 = .[a1:a1500]
         strMyChar = rep.Value
         replace = rep.Offset(0, 2).Value   '-> offset range to date location (range)
        strMyReplace = rep.Offset(0, 1).Value
               With Rng2
                     If replace = Mydate Then    'type mismatch here
                           .replace What:=strMyChar, Replacement:=strMyReplace, _
                            SearchOrder:=xlByColumns, MatchCase:=True
                     End If
        End With
Next rep