Shift scenery as required (9)
I believe the answer is:
necessary
'required' is the definition.
(similar in meaning)
'shift scenery as' is the wordplay.
'shift' is an anagram indicator.
'scenery'+'as'='sceneryas'
'sceneryas' is an anagram of 'NECESSARY'.
(Other definitions for necessary that I've seen before include "Needful" , "Required, needed" , "obligatory" , "Indespensable, essential" , "Vital" .)