Is it permissible for the muezzin to lead the congregational prayer after having made the call to prayer (Iqama)?

It is permissible for one person to undertake both the Adhan (call to prayer) and the Imamate (leading the prayer). If the Mu'adhin (caller to prayer) is the most knowledgeable among those present, he may lead them in prayer as Imam. Similarly, if the regular Imam is absent and he deputizes him, it is also permissible for him to be appointed to the position of the regular Imam.