Checkbox reference

Afternoon all

I am using the following code

Sub Process_CheckBox()

    Dim cBox As CheckBox
    Dim LRow As Integer
    Dim LRange As String

    LName = Application.Caller
    Set cBox = ActiveSheet.CheckBoxes(LName)

    'Find row that checkbox resides in
    LRow = cBox.TopLeftCell.Row
    LRange = "B" & CStr(LRow)

    'Change date in column B, if checkbox is checked
    If cBox.Value > 0 Then
        ActiveSheet.Range(LRange).Value = Date

    'Clear date in column B, if checkbox is unchecked
    Else
        ActiveSheet.Range(LRange).Value = Null
    End If

End Sub

I would like to amend this for a single check box so to not look at the check box row column B but rather an actual reference of C21.

Should eb fairly straight forward can someone help???

Thanks

N