You may reveal Deal Broker itself for its second ability. If you do, and you accept another player's offer, that player won't be able to use the second ability to offer another exchange.

When you use Deal Broker's second ability, after you reveal your card, each other player chooses up to one card from their card pool, then all those chosen cards are revealed simultaneously.

If you accept a player's offer, the card you revealed becomes part of that player's card pool and the other offered card becomes part of your card pool.

The cards exchanged this way aren't drafted. They can't be removed from the draft by Cogwork Grinder, for example.

If either card involved in the exchange has any information noted for it, that information stays with the exchanged card, not the player who initially drafted it. Any abilities that refer to actions taken as you drafted the card (or similar) now refer to the card's new owner, even though that player wasn't the person who actually drafted the card.

If a player exchanges a card that has multiple pieces of information noted for it, all of the information is shared during the exchange. For example, if you receive a Cogwork Tracker from a player who drafted multiple Cogwork Trackers, your Cogwork Trackers may attack any player noted by either you or the other player for Cogwork Tracker. The other player will not remove a noted player from their remaining Cogwork Tracker.

If more than one player drafts a Deal Broker, players who wish to use the second ability to exchange cards do so in a random order.

If your draft is breaking up into multiple games, the exchange happens before it's known who will be playing in each game.