Prophet said (to two persons), "Whenever the prayer time becomes due, you should pronounce Adhan and then Iqama and the older of you should lead the prayer."  

عَنِ النَّبِيِّ ﷺ قَالَ إِذَا حَضَرَتِ الصَّلاَةُ فَأَذِّنَا وَأَقِيمَا ثُمَّ لِيَؤُمَّكُمَا أَكْبَرُكُمَا