Answered by Shaykh Faraz Rabbani
Is it valid in Hanafi school to establish a Jammat prayer by tapping on somebody’s shoulder? If this is valid, then is it ok to move forward (in case if one becomes imam) in the front row? My concern is that this may account for excessive movement in the prayer, not recommended in Hanafi school.
One can do this to initiate prayer, on condition that one is reasonably sure that the person leading is (1) performing the obligatory prayer and (2) they aren’t completing a prayer in which they were following someone else.
(Ref: Ibn Abidin, Radd al-Muhtar; Fatawa Hindiyya)
Please search SunniPath Answers (http://qa.sunnipath.com) for related answers.