Call up to have a trial for City (8)
I believe the answer is:
budapest
'city' is the definition.
(Budapest is an example)
'call up to have a trial' is the wordplay.
'call' becomes 'dub' (dubbing is a kind of calling**).
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'to have' means one lot of letters go next to another.
'trial' becomes 'pest' (both can mean an annoying person).
'dub' in reverse letter order is 'bud'.
'bud'+'a'+'pest'='BUDAPEST'
'for' acts as a link.
(Other definitions for budapest that I've seen before include "Hungarian capital" , "European capital" , "capital location" , "capital of Europe" , "Ernest Laszlo's birthplace" .)