Sunan an-Nasa'i, Book 6, Hadith 620 (In-Book)

It was narrated that Anas said: The Messenger of Allah said: "Whoever forgets a prayer, let him pray it when he remembers it."

أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ مَنْ نَسِيَ صَلاَةً فَلْيُصَلِّهَا إِذَا ذَكَرَهَا ‏" ‏ ‏.‏

sunnah.com