Amadeus has launched an ancillary services tool through which U.S. users can book or upgrade travelers to United Airlines' Economy Plus seats,

the company announced Wednesday. Users in Puerto Rico and the Virgin Islands also can use the tool, Amadeus announced. The tool uses the International Air Transport Association's New Distribution Capability XML-based program, making it the first agency channel in North America to use the platform. United and Amadeus also are planning to implement the tool to sell Economy Plus seats in other global markets, according to Amadeus.