Change in an international terminal (5)
I believe the answer is:
alter
'change' is the definition.
(I know that change can be written as alter)
'in an international terminal' is the wordplay.
'in' says the answer is hidden in the clue.
'ALTER' is hidden within 'international terminal'.
(Other definitions for alter that I've seen before include "Revise" , "and 10 Across: Second self" , "shift" , "reform" , "Change, make different" .)