Fixed agenda modified to accommodate bishop (8)
I believe the answer is:
arranged
'fixed' is the definition.
(fix can mean to arrange or organise)
'agenda modified to accommodate bishop' is the wordplay.
'modified' indicates an anagram.
'to accommodate' means one lot of letters goes inside another.
'bishop' becomes 'rr' (abbreviation for Right Reverend).
'agenda' anagrammed gives 'aanged'.
'aanged' placed around 'rr' is 'ARRANGED'.
(Other definitions for arranged that I've seen before include "Settled plans for something" , "Placed attractively as with flowers" , "Scored" , "Ordered" , "Organised, planned" .)