Head to destination by alternative route (6)
I believe the answer is:
detour
'head to destination by alternative route' is the definition.
I can't tell whether this definition defines the answer.
'head to destination by alternative route' is the wordplay.
'head to' suggests taking the first letters.
'by' is a charade indicator (letters next to each other).
'alternative' indicates an anagram.
The initial letter of 'destination' is 'd'.
'route' is an anagram of 'etour'.
'd'+'etour'='DETOUR'
(Other definitions for detour that I've seen before include "Way round the roadblock" , "A way round, say, road works" , "Temporary roundabout way" , "Roundabout route, to avoid something say" , "Diversion" .)