User selected merged cell range to be cleared

User get question to select area to be cleared.
Only need to be a present merged cell range that is entitled for clearance.
I face problem to implement it. Anybody able to help me.

Macro need to start with inputpox.

Private Sub CmdClear_Click()
On Error GoTo error_handler
Set srng = Application.InputBox(prompt:= _
  "Select Appointment to be cleared", Type:=8)
With srng
Dim I As Integer
    With ActiveCell.MergeArea
End With
error_handler:
Exit Sub
    End With
    ActiveCell.Select
    End Sub