The Rules of Ultimate
Key New Rule
Difference to USAU
15. Calling Fouls Infractions and Violations
15.1. A breach of the rules due to non-minor contact between two or more opposing players is a foul.
15.3. Every other breach of the rules is a violation.
15.5. In general only the thrower may claim an infraction, by calling the specific name of the infraction.
15.6. Any opposing player may claim a violation, by calling the specific name of the violation or "Violation", unless specified otherwise by the particular rule.
15.7. When a foul or violation call is made that stops play, players must stop play by visibly or audibly communicating the stoppage as soon as they are aware of the call and all players should echo calls on the field. If play has stopped for a discussion without any call having been made, a call is deemed to have been made when the discussion started.
15.9.1. if the opposition gains or retains possession, any subsequent play stands.
15.9.2. if the opposition does not gain or retain possession, the disc must be returned to the last non-disputed thrower, unless 16.3 applies. The stall count resumes as if an accepted breach has been caused by the player who initiated the stoppage incorrectly.
15.11. If a player making any call subsequently determines that their call was incorrect, they can retract the call, by calling "Retracted". The stall count resumes as if an accepted breach has been caused by that player.