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EDIFACT message guide · Travel and tourism

RESREQ Reservation request

The UN/EDIFACT interactive message a customer or agent sends to reserve, modify or cancel a travel, tourism or leisure service.

Sent by
Customer, travel agent or booking system
Received by
Travel service provider
Standard
UN/EDIFACT · Interactive (I-EDI) message
X12 equivalent
No direct equivalent

What is the EDIFACT RESREQ message?

RESREQ is the UN/EDIFACT interactive travel, tourism and leisure reservation request. The directory defines it as a message sent by a customer or their agent to a service provider to reserve, modify or cancel a travel, tourism or leisure service. The result is returned in the interactive reservation response (RESRSP).

As an interactive (I-EDI) message, the request and response form one real-time dialogue: the booking system waits for the answer and shows it to the traveler or agent immediately, unlike batch reservations processed later.

How the EDIFACT RESREQ message worksDiagram of the UN/EDIFACT RESREQ Reservation request message. Customer, travel agent or booking system sends it to travel service provider. It usually follows AVLRSP. It is usually followed by RESRSP. Inside the UIB and UIH envelopes, the directory D.21A requires, in the . 6 conditional segment groups are listed by their trigger segment.How the EDIFACT RESREQ message worksReservation request: who sends it, where it fits and what the directory marks mandatory1 WHERE IT FITSUSUALLY FOLLOWSAVLRSPAvailability responseRESREQSENDERCustomer, travel agentor booking systemRECEIVERTravel service providerUSUALLY FOLLOWED BYRESRSPReservation response2 WHAT DIRECTORY D.21A REQUIRESInteractive interchangeUIB … UIZMessage RESREQUIH … UITBODY AND SEGMENT GROUPS+ 6 conditional groups, starting with:NMESSRPMTTIFTVLODIBlue box: mandatory segment group. Conditional groups are listed by the trigger segment that starts them; a group is sent only when its data applies.Conditional segments outside groups are not drawn.Structure: mandatory segments and groups in the UN/EDIFACT directory D.21A listing for RESREQ. Your trading partner's implementation guide adds itsown requirements.
How the EDIFACT RESREQ message worksDiagram of the UN/EDIFACT RESREQ Reservation request message. Customer, travel agent or booking system sends it to travel service provider. It usually follows AVLRSP. It is usually followed by RESRSP. Inside the UIB and UIH envelopes, the directory D.21A requires, in the . 6 conditional segment groups are listed by their trigger segment.How the EDIFACT RESREQmessage worksReservation request: who sends it, where it fitsand what the directory marks mandatory1 WHERE IT FITSUSUALLY FOLLOWSAVLRSPAvailability responseRESREQSENDERCustomer, travelagent or bookingsystemRECEIVERTravel serviceproviderUSUALLY FOLLOWED BYRESRSPReservation response2 WHAT DIRECTORY D.21A REQUIRESInteractive interchange (UIB … UIZ)Message RESREQ (UIH … UIT)BODY AND SEGMENT GROUPS+ 6 conditional groups, starting with:NMESSRPMTTIFTVLODIBlue box: mandatory segment group. Conditionalgroups are listed by the trigger segment thatstarts them; a group is sent only when its dataapplies. Conditional segments outside groups arenot drawn.Structure: mandatory segments and groups in theUN/EDIFACT directory D.21A listing for RESREQ.Your trading partner's implementation guide adds itsown requirements.

How to read this diagram: the top row shows who sends RESREQ, to whom, and which messages usually come before and after it. The lower part shows what the directory D.21A itself requires: the envelopes around RESREQ and the segments and segment groups it marks mandatory. Conditional groups are listed by their trigger segment rather than drawn in full. This is the directory's minimum, not a trading partner's requirement: a message implementation guide usually makes some conditional groups mandatory, restricts the codes and may use an older directory.

Expand diagram Download SVG

When it is used

  • Booking travel services in real time
  • Modifying an existing reservation
  • Cancelling a reservation

Where it fits in the message flow

Usually follows AVLRSP Availability response
This message RESREQ Reservation request
Usually followed by RESRSP Reservation response

Structure

Mandatory segments in RESREQ (directory D.21A)

In UN/EDIFACT directory D.21A, the RESREQ message has 108 segment positions arranged in 20 segment groups. These are the segments and segment groups marked mandatory at message level, in order; a mandatory group is shown with the segment that starts it. Segments inside conditional groups are needed only when the group is used. This is the directory’s requirement, not your trading partner’s: each partner’s message implementation guide names the directory it uses, often an older one such as D.96A or D.01B where the structure can differ, makes some conditional segments mandatory and restricts the codes. This structure comes from one published copy of the directory and has not been independently verified: confirm it before you build a map.

  • UIH
  • UIT

Practical example

RESREQ in practice

A travel agent finds an available rail journey for a client and books it. The agency's booking system sends the rail operator a RESREQ with the journey, class and passenger details. The operator answers within seconds with a RESRSP confirming the seats and the booking reference.

Implementation

Implementation considerations for RESREQ

  • Design for real-time response times and timeouts.
  • Avoid duplicate bookings when requests are retried.
  • Protect travelers' personal data under applicable law.
  • Check which interactive standards each provider supports.

How ECOM helps

Automate RESREQ with ECOM

Industry

Hospitality

Procurement, invoicing and supplier integration for hotels, restaurant groups and foodservice suppliers.

Solution

Batch and Real-Time Integration

Scheduled batch processing and real-time, API-driven integration on one platform.

Solution

API Integration

Connect partner and application APIs to your systems and bridge them with EDI processes.

Compare X12 and EDIFACT, or see answers to general questions in the EDI FAQ.

Related messages

Related travel and tourism messages

All 16 travel and tourism messages

Need help with RESREQ?

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