Update arbiter regarding southern hospital (7)
I believe the answer is:
refresh
'update' is the definition.
(refresh can mean to update)
'arbiter regarding southern hospital' is the wordplay.
'arbiter' becomes 'ref' (I've seen this in another clue).
'regarding' becomes 're' ('re' means regarding or about).
'southern' becomes 's' (abbreviation).
'hospital' becomes 'H' (abbreviation for hospital).
'ref'+'re'+'s'+'h'='REFRESH'
(Other definitions for refresh that I've seen before include "Breathe new life into" , "Renew" , "brace" , "Give new vigour to" , "perk up!" .)