PMS Reservation Sync (HTNG) SOAP API 10.33 The PMS Reservation Sync (HTNG) (OTA_HotelResNotifRQ) API is used to communicate reservation data from a PMS to SynXis CRS. The PMS Reservation Sync (HTNG) (OTA_HotelResNotifRQ) API is used to communicate reservation data from a PMS to SynXis CRS. Property Connect HTNG Reservations Data Migration PMS Integration