Observes section being rebuilt (7)
I believe the answer is:
notices
'observes' is the definition.
(noticing is a kind of observing)
'section being rebuilt' is the wordplay.
'being rebuilt' is an anagram indicator.
'section' with letters rearranged gives 'NOTICES'.
(Other definitions for notices that I've seen before include "reviews" , "Observes the public proclamations" , "Discovers" , "Section (anag) - spots" , "Sees; adverts" .)