When the Messenger of Allah ﷺ offered salutation in the witr prayer, he said: Glorify be to the king most holy.  

كَانَ رَسُولُ اللَّهِ ﷺ إِذَا سَلَّمَ فِي الْوِتْرِ قَالَ سُبْحَانَ الْمَلِكِ الْقُدُّوسِ  

The Prophet ﷺ said: If anyone oversleeps and misses the witr, or forgets it, he should pray when he remembers.  

قَالَ رَسُولُ اللَّهِ ﷺ مَنْ نَامَ عَنْ وِتْرِهِ أَوْ نَسِيَهُ فَلْيُصَلِّهِ إِذَا ذَكَرَهُ