If worried, please pass (6)
I believe the answer is:
elapse
'pass' is the definition.
(I've seen this before)
'if worried please' is the wordplay.
'if worried' indicates anagramming the letters.
'please' with letters rearranged gives 'ELAPSE'.
(Other definitions for elapse that I've seen before include "pass in silence" , "Pass or expire - please" , "Passing" , "Slip away" , "Of time, pass by - please" .)