Adds to the fashionable lines (9)
I believe the answer is:
increases
'adds' is the definition.
The definition and answer can be both related to change as well as being verbs in their -s form.
Maybe they are linked in a way I don't understand?
'the fashionable lines' is the wordplay.
'the fashionable' becomes 'in'.
'lines' becomes 'creases' ('crease' can be a synonym of 'line'**).
'in'+'creases'='INCREASES'
'to' is the link.
Can you help me to learn more?
(Other definitions for increases that I've seen before include "Becomes bigger" , "Becomes greater" , "Gets bigger" .)