Did coach change route within Thailand's borders? (7)
I believe the answer is:
tutored
'did coach' is the definition.
(coach can mean to tutor)
'change route within thailand's borders?' is the wordplay.
'change' is an anagram indicator.
'within' means one lot of letters goes inside another.
'borders?' suggests removing the centre (I've seen 'borders' mean this (only the edge or border letters remain)).
'thailand' with its middle taken out is 'td'.
'route' anagrammed gives 'utore'.
'utore' inserted into 'td' is 'TUTORED'.
(Other definitions for tutored that I've seen before include "Coached" , "Taught small groups" , "Was coach" , "Instructed" , "Rude tot (anag.)" .)