You cannot extend a booking under the following circumstances:
1- If you have already extended the booking, the original booking (the first booking which has been extended) cannot be extended. However, you can extend the second (extended) booking.
2- If the booking status is Cancelled or Scheduled for Cancellation.
3- If your invoice has been Completed. (You can change it to Draft if you want to extend the booking)
4- If your invoice has been sent to Xero.(You can void it if you want to extend the booking)
5- If the booking status is Pending Finalisation or Finalised or Finalisation in Progress.
6- If the booking status is No Show.