Choose not to participate in work with aggressive solicitor? (3,3)
I believe the answer is:
opt out
'choose not to participate' is the definition.
(to opt out of something is to choose not to do it)
'work with aggressive solicitor?' is the wordplay.
'work' becomes 'op' (common abbreviation for 'opus').
'with' says to put letters next to each other.
'aggressive solicitor?' becomes 'tout' (someone who solicits business).
'op'+'tout'='OPT-OUT'
'in' is the link.
(Other definitions for opt out that I've seen before include "Decide not to participate" , "Choose not to participate" , "Decide to withdraw" , "Choose not to do something" , "Decline to participate" .)