Request measure leading to agreement (8)
I believe the answer is:
entreaty
'request' is the definition.
(entreaty is a kind of request)
'measure leading to agreement' is the wordplay.
'measure' becomes 'en' (typographical measure).
'leading to' means one lot of letters go next to another (some letters go before or lead others).
'agreement' becomes 'treaty' (treaty is a kind of agreement).
'en'+'treaty'='ENTREATY'
(Other definitions for entreaty that I've seen before include "Appeal" , "Earnest or urgent request" , "application for assistance" , "suit" , "petition" .)