"It is not appropriate for the Imam, if he becomes impure (breaks his wudu'), to appoint someone else to lead except for someone who was present from the beginning of the iqamah (call to start the prayer). If he appoints someone who has missed a rak'ah, it should not be done." Abdullah ibn Sinan narrated from him (as) that He said: "When the Imam completes his prayer with the congregation, he should gesture to them to the right and left so they can disperse, and then he should complete whatever part of the prayer he missed."