Macro not working properly for conversion of date format

Hi,

In the attached sheet, one macro is developed which is not working properly. Can anyone help me.

My req is to convert date from dd-mon-yyyy to yyyy/mm/dd format. (23-jan-2010--> 2010/01/23)

If incomplete date is there, then hyphen should place the gap i.e.

For date like APR-2014------> Output should be 2014/04/--
For date like 1998 -----> Output should be 1998/--/--

The below macro works only for row number 11, 15 and 16. can anyone have a look on it

ub date1()
Dim c As Range, sNF
With Sheet1
    For Each c In Range("J2:J" & .Cells(Rows.Count, 10).End(xlUp).Row)
        If c.Value <> "" Then
            sNF = c.NumberFormat
            c.NumberFormat = "@"
            Select Case sNF
                Case "dd-mmm-yyyy hh:mi:ss":     c.Value = Format(c.Value, "yyyy/mm/dd")
                Case "dd-mmm-yyyy":     c.Value = Format(c.Value, "yyyy/mm/dd")
                Case "mmm-yyyy":        c.Value = Format(c.Value, "yyyy/mm/--")
                Case "General":         c.Value = c.Value & "/--/--"
            End Select
        End If
    Next c
End With
End Sub