All Schema files in the OTA specification are made available according to the terms defined by the OTA License Agreement at http://www.opentravel.org/ota_downloads_form.cfm Sends a request for a reservation to another system.There is no requirement to determine availability prior to sending a reservation request. Travel agencies, or individual guests may send a request to book a reservation from an internet site if all the information required for booking is known. The OTA_HotelResRQ message can initiate the first message in the sequence of booking a reservation.