The name "Gentleman's Re-Rack" alludes to the fact that it can be called even if all of the teams re-racks are exhausted, and it is seen as a gentlemanly gesture to grant them one last re-rack (seeing as the last two cups are often far away from one another).
Unlike normal re-racks, a "Gentleman's" can be called mid-turn. Although a call for a "Gentleman's" can legally be rejected, the team that rejects it will forever be labeled selfish cowards.
The actual structure of a "Gentleman's Re-Rack" is two cups in a vertical line, running parallel to the sides of the table.
Team 2 "yeah sure"
Team 1 "Can you straighten that out a bit?"
Team 2 "No doubt."