Serving flier has sorties to rearrange (3,7)
I believe the answer is:
air hostess
'serving flier' is the definition.
(someone who flies in planes)
'has sorties to rearrange' is the wordplay.
'to rearrange' indicates an anagram (I've seen 'rearranged' mean this).
'has'+'sorties'='hassorties'
'hassorties' anagrammed gives 'AIR-HOSTESS'.
(Other definitions for air hostess that I've seen before include "Female flight attendant" , "Serving flyer" , "Female working in plane" , "high flyer" , "Stewardess on a plane" .)