Note route changed to bypass (6)
I believe the answer is:
detour
'bypass' is the definition.
(I've seen this in another clue)
'note route changed' is the wordplay.
'note' becomes 'd' (musical note).
'changed' indicates an anagram.
'route' anagrammed gives 'etour'.
'd'+'etour'='DETOUR'
'to' is the link.
(Other definitions for detour that I've seen before include "Way round the roadblock" , "Temporary roundabout way" , "Diversion" , "Temporary route" , "Deviate from planned route, go around" .)