.. _Book-ancillaries-for-existing-booking:

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Book Ancillaries for existing booking
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   <h3>Workflow description</h3>

To add ancillaries to an existing booking, the client can retrieve the booking (optional, see :ref:`Retrieve-existing-booking`)

- Seat availability to get the seatmap including free/blocked searts and their properties (see :ref:`Retrieve-seatmap`)
- Service list to get the available SSRs (see :ref:`Retrieve-service-catalogue`)

The request to update the existing booking is an IATA_ServiceDeliveryNotifRQ message (the same as for creation of a booking)

See :ref:`Deliver-booking` for details.

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   <h3>Message Flow</h3>

.. image:: ../images/Update_booking_add_ancillaries.png