Programming a confirm overwrite message box

[duality1984]

Hello all,

This is my first post and I apologise if it's in the wrong place.

I have created a user form that allows various choices to be checked, which are then put into a cell in the spreadsheet.

However, I want a 'confirm overwrite? (yes/no)' message to be displayed if there is data already in the cell - clicking yes proceeds to overwrite and clicking no aborts the overwrite procedure.

Here is the code I already have, which is assigned to the OK box:

Private Sub CommandButton6_Click()

Dim ws As Worksheet
Set ws = Worksheets("Sheet1")

Dim str As String

For Each ctr In Me.Controls

If (ctr) Then
    str = str + ctr.Caption + ", "
    End If
    
Next ctr

'ActiveCell

ws.Cells(ActiveCell.Row, 9).Value = str

Unload Me

End Sub

Any help is much appreciated.