Dim conn As ADODB.Connection
Dim cmd As ADODB.Command
Dim CommitOK As Boolean
CommitOK = True


Set conn = CurrentProject.Connection
Set cmd = New ADODB.Command
Set cmd.ActiveConnection = conn
cmd.CommandType = adCmdText
cmd.CommandText = "BEGIN TRANSACTION"
cmd.Execute

cmd.CommandText = "DELETE  From MyTable WHERE MyTable.MyField=" & MyParameter
cmd.Execute
 ' Тут должно быть присвоение значения CommitOK  

If CommitOK Then
  cmd.CommandText = "COMMIT TRANSACTION"
  cmd.Execute
  MsgBox "Задание выполнено!", vbInformation
Else
  cmd.CommandText = "ROLLBACK TRANSACTION"
  cmd.Execute
  MsgBox "Операция отменена!", vbInformation
End If