It is preferable that the person who calls the Adhan should also call the Iqamah. If the Mu'adhin feels displeased by someone else calling the Iqamah, then it is Makruh (disliked) for the other person to call the Iqamah, because calling the Iqamah is the right of the Mu'adhin. However, if in the absence of the Mu'adhin or with his permission, another person calls the Iqamah, then it is permissible without any dislike (Karahat). (Aham Masail / Vol: 5 / Pg: 75)