Follow, otherwise adapt (6)
I believe the answer is:
tailor
'adapt' is the definition.
(I know that tailor is a more specific form of adapt)
'follow otherwise' is the wordplay.
'follow' becomes 'tail' (both can mean to chase or pursue).
'otherwise' becomes 'or'.
'tail'+'or'='TAILOR'
(Other definitions for tailor that I've seen before include "Maker of fitted clothes" , "Maker of clothes, men's mostly" , "fitter" , "Garment maker" , "Seamster" .)