Space traveller altering aunt's rota (9)
I believe the answer is:
astronaut
'space traveller' is the definition.
(I've seen this before)
'altering aunt's rota' is the wordplay.
'altering' indicates anagramming the letters.
'aunts'+'rota'='auntsrota'
'auntsrota' anagrammed gives 'ASTRONAUT'.
(Other definitions for astronaut that I've seen before include "Person trained to travel in a spacecraft" , "Skier" , "For member of high-flying mission" , "Space voyager" , "Santa tour for space traveller" .)