41 CFR § 301-50.6
What is an “online self-service booking tool?”
June 9, 2020
An online self-service booking tool is an Internet based system that permits travelers to make their own reservations for transportation (e.g., air, rail, and car rental) and lodging. ETS and some agency TMS's incorporate a self service booking tool.
[FTR Amdt. 2006-04, 71 FR 49375, Aug. 23, 2006]