Facilitate rental agreement, saving pounds (4)
I believe the answer is:
ease
'facilitate' is the definition.
('ease' can be a synonym of 'facilitate')
'rental agreement saving pounds' is the wordplay.
'rental agreement' becomes 'lease' (I've seen this before).
'saving' indicates named letters should be taken away (saving can mean except).
'pounds' becomes 'l' (L can represent the monetary pound).
'lease' with 'l' taken out is 'EASE'.
(Other definitions for ease that I've seen before include "Freedom from worry" , "Effortlessness" , "Lack of difficulty" , "Lessen intensity" , "Leisure, relaxation" .)