Can he pray Witr twice in one night if he prays after the imam?

I want to ask whether at the end of Taraaweeh prayer we should pray
al-Shaf' [two rak'ahs of naafil prayer] and Witr? I heard that the
last prayer you pray should be Witr. Does that mean that if I get up
to pray qiyaam al-layl I should pray al-Shaf' and Witr again, orshould
I delay them until Ipray qiyaam and then pray it?.
Praise be to Allaah.
If the Muslim prays Witr then he wants to pray qiyaam al-layl after
that, he should pray them two by two, and he does not have to repeat
Witr.
The Prophet (peace and blessings of Allaah be upon him) commanded that
the last prayer offered at night should beWitr, but this command is in
the sense that is it mustahabb, not obligatory. See Question no. 37729
.
Shaykh Ibn Baaz was asked:
If I have prayed Witr at the beginning of the night, then I get up to
pray qiyaam at the end ofthe night, how should I pray?
He replied:
If you have prayed Witr atthe beginning of the nightthen Allaah
enables you to get up at the end of the night, then pray whatever you
can two by two – without Witr, because the Prophet (peace and
blessings of Allaah be upon him) said: "There cannot be no two Witrs
in one night."
And it was narrated from 'Aa'ishah (may Allaah be pleased with her)
that theProphet (peace and blessings of Allaah be upon him) used to
pray two rak'ahs after Witr sitting down. The reason for that – and
Allaah knows best – was to show the people that it is permissible to
pray after Witr.

Majmoo' Fataawa al-Shaykh Ibn Baaz.

And Allaah knows best.