why does iago send emilia to cassio ?

The third act begins with a little bit of comic relief; a clown is mincing words with a few musicians, then has a little wordplay with Cassio, who bids the clown to go and see if Desdemona will speak with him. Iago enters, and Cassio tells him that he means to speak to Desdemona, so that she may clear things up with Othello. Emilia comes out, and bids Cassio to come in and speak with Desdemona about his tarnished reputation.