A man of Banu Amir told that he asked the Prophet ﷺ for permission (to enter the house) when he was in the house, saying: May I enter ? The Prophet ﷺ said to his servant: Go out to this (man) and teach him how to ask permission to enter the house, and say to him: "Say : Peace be upon you. May I enter?" The man heard it and said: Peace be upon you! May I enter ? The Prophet ﷺ permitted him and he entered. (Using translation from Abū Dāʾūd 5177)   

أَنَّهُ اسْتَأْذَنَ عَلَى النَّبِيِّ ﷺ فَقَالَ أألِجُ؟ فَقَالَ النَّبِيُّ ﷺ اخْرُجْ إِلَيْهِ فَإِنَّهُ لَا يُحْسِنُ الِاسْتِئْذَانَ فَقُلْ لَهُ فَلْيَقُلِ السَّلَامُ عَلَيْكُمْ أَأَدْخُلُ فَسَمِعْتُهُ يَقُولُ ذَلِكَ فَقُلْتُ السَّلَامُ عَلَيْكُمْ أَأَدْخُلُ؟ فَأَذِنَ لِي فَدَخَلْتُ