Hail

From Starport: Galactic Empires

The Hail order is used to accomplish trades between captains. Use the telephone/communications button on the right hand side of the screen to bring up a list of nearby players who can be hailed. Players who are not nearby can also be hailed by unchecking the "In-System Players Only" box, but only Credits, Tokens, and Contractor Status can be traded.

When the other player accepts the offer to begin trading, you will see the trade screen with areas in which each of the parties can offer credits or items for a trade. This is also the way duels are started. The trade will not happen until both parties ratify it. Any change to the offer by either party will reset the ratification process.