Convert string dates to proper numerical date format

Hello, Everyone!

I am trying to convert text 'dates' like Sat. 1/05/2007 to real dates. I need to find all 'date' cells in range B4:B100 (they are filled in yellow), strip off the offending text (i.e. Sat.), and use DateValue to turn the rest into a proper, numerical date in the ddd mm/dd/yy format, arial, bold, 10pt, and centered in place.

I've spent days trying to write this macro. I've had help from experts in forums, but whenever I need to make any slight modification, a
trainwreck ensues. Please see the code below.

Sub switchDate()
Dim MyDate As String
For Each cell In ActiveSheet.Range("B4:B100")
    If cell.Interior.ColorIndex <> xlNone Then
       cell.Value = MyDate.Value
            MyDate = Trim(MyDate)
            If InStr(MyDate, " ") > 0 Then
            MyDate = Mid(MyDate, InStr(MyDate, " ") + 1)
            End If
        MyDate = DateValue(MyDate)
    End If
Next
End Sub

This doesn't even begin to work and I can't begin to guess why. Could
somebody out there please make the tweaks and tell me what I did wrong, that I might not do it hence?

I thank you greatly, and have a terrific day.

Arlen