Question: If I performed the Witr prayer during the first part of the night and then I woke up during the latter part of the night, how shall I pray?
Response: If you made Witr during the first part of the night and then Allaah made it easy for you to get up in the later part of the night, then pray whatever Allaah has made easy for you in sets of two without performing another Witr. This is because the Prophet (sal-Allaahu �alayhe wa sallam) said, "There are not to be two Witrs in one night."1 Furthermore, �Aa.ishah reported that the Prophet (sal-Allaahu �alayhe wa sallam) used to pray two rak'ahs after Witr, while he was sitting. The wisdom behind that, Allaah knows best, is to show the people that it is permissible to pray after the Witr prayer.
Shaykh Ibn Baaz
Fataawa al-Mar.ah