It is recommended that the person who called to prayer should also establish it. However, if someone else establishes it: if the caller to prayer is bothered by this, it is disliked; because causing harm to a Muslim is disliked. If he is not bothered, then it is not disliked. As narrated by Ziyad Al-Sada'i, may Allah be pleased with him, who said: 'The Messenger of Allah, peace and blessings be upon him, commanded me to call to the Fajr prayer, so I called to it. Bilal wanted to establish it, but the Messenger of Allah, peace and blessings be upon him, said: The brother of Sada' has called to prayer, and whoever calls to prayer should establish it.' This is found in Sunan al-Tirmidhi 1: 383, Sunan al-Sughra 1: 207, Sunan al-Bayhaqi al-Kubra 1: 381, Sunan Abi Dawood 1: 142, Sunan Ibn Majah 1: 237, Sharh Ma'ani al-Athar 1: 142, and Musnad Ahmad 4: 169. See: Al-Bada'i 1: 149-152.