Overwrite if file name already exists

Hi, I was looking for a macro code which would save attachments and save them with the email subject to a specific folder on my network. I have found this by Graham Major which is excellent and ideal for what I need.
Is it possible that it can be amended to check if the file name already exists and overwrite it with the latest email attachment?

Many Thanks

Code:

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Sub Test()Dim olMsg As MailItem
    On Error Resume Next
    Set olMsg = ActiveExplorer.Selection.Item(1)
    Save_As_Subject olMsg
lbl_Exit:
    Exit Sub
End Sub


Sub Save_As_Subject(olItem As MailItem)
'Graham Mayor - http://www.gmayor.com - Last updated - 13 Jan 2018
Dim olAttach As Attachment
Dim strFileName As String
Dim strExt As String
Const strPath = "Y:\accounts\Conv slips\"    'the path to store the files


    For Each olAttach In olItem.Attachments
        strExt = Mid(olAttach.FileName, InStrRev(olAttach.FileName, Chr(46)))
        Select Case LCase(strExt)
            Case Is = ".docx", ".dotx", ".pdf", ".xlsx", ".zip", ".html", ".jpeg", ".txt", "xls", ".htm", ".doc"  'the wanted extensions
                strFileName = olItem.Subject
                strFileName = CleanFileName(strFileName)
                strFileName = strPath & strFileName & strExt
                olAttach.SaveAsFile strFileName
            Case Else
        End Select
    Next olAttach
lbl_Exit:
    Set olItem = Nothing
    Set olAttach = Nothing
    Exit Sub
End Sub


Private Function CleanFileName(strFileName As String) As String
    'Graham Mayor - http://www.gmayor.com - Last updated - 05 Jul 2017
    'A function to ensure there are no illegal filename
    'characters in a string to be used as a filename
    Dim arrInvalid() As String
    Dim vfName As Variant
    Dim lng_Name As Long
    Dim lng_Ext As Long
    Dim lngIndex As Long
    CleanFileName = strFileName
    'Define illegal characters (by ASCII CharNum)
    arrInvalid = Split("9|10|11|13|34|42|47|58|60|62|63|92|124", "|")
    'Add the extension to the filename
    CleanFileName = CleanFileName
    'Remove any illegal filename characters
    For lngIndex = 0 To UBound(arrInvalid)
        CleanFileName = Replace(CleanFileName, Chr(arrInvalid(lngIndex)), Chr(95))
    Next lngIndex
lbl_Exit:
    Exit Function
End Function

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