Seeing changes within a couple of days, as planned (8)
I believe the answer is:
designed
'planned' is the definition.
('design' can be a synonym of 'plan')
'seeing changes within a couple of days' is the wordplay.
'changes' is an anagram indicator.
'within' is an insertion indicator.
'a couple of' indicates the doubling of some letters.
'days' becomes 'd'.
'seeing' anagrammed gives 'esigne'.
'd' duplicated is 'dd'.
'esigne' going into 'dd' is 'DESIGNED'.
'as' is the link.
(Other definitions for designed that I've seen before include "Intended; drew" , "Meant" , "Planned or conceived for a specific purpose" , "Make a drawing or blueprint" , "Made a drawing or blueprint" .)