Finding a date format

thanks a lot for the reply this is working,

but it would be greae ful if you can give some light about the using of offset function with date function......
because i wnat to chnage the format of dates put values against that dates from the range.

i prepared a code with the help of above mentioned code but it is not running correctly it takes the dates as the cell value
Sub finddates()
Dim ccell As Range
Dim bcell As String
Dim dcell As String
Dim ap As String

bcell = CStr(InputBox("enter holidays"))
dcell = CStr(InputBox("previous day"))

For Each ccell In Range("a1:a50")
If IsDate(ccell) = True Then
'ccell.Value = Format(ccell, "DD--MM--YYYY")
ap = "=networkdays" & "(" & ccell & "," & dcell & "," & bcell & ")"
ccell.Offset(0, 2) = ap

End If
Next ccell
End Sub

please suggest