Cassio Gets Demoted?

Othello and Cassio are sent off to a battle; after they finish their duties they are seperated and Cassio comes back first.  When Cassio comes back he attends a party where Iago trys to make him drink.  He was so drunk that he chased Rodreigo across the room and Montano getting in the way gets stabbed.  Iago orders Roderigo to leave and “cry a mutiny”  With that call Othello arrives and demands to meet with Cassio and Iago.  Othello demands to know what happened but, neither of the two would say anything.  Iago finally budges and tells Othello what happened.  Othello then takes Cassio's sash away and gives it to Iago.  Desdemona feels bad for Cassio and wants to help so she trys to tell Othello to forgive him.  Iago sets up his plan to make up Cassio and Desdemona's affair.