Delete part of opera section (5)
I believe the answer is:
erase
'delete' is the definition.
(I know that delete can be written as erase)
'part of opera section' is the wordplay.
'part of' says the answer is hidden in the clue.
'ERASE' is hidden within 'opera section'.
(Other definitions for erase that I've seen before include "Clear" , "Scratch" , "Kill" , "Delete" , "Remove, wipe out" .)