Beg agreement on public relations (4)
I believe the answer is:
pray
'beg' is the definition.
(I know that beg can be written as pray)
'agreement on public relations' is the wordplay.
'agreement' becomes 'ay'.
'on' says to put letters next to each other.
'public relations' becomes 'PR' (abbreviation).
'ay' after 'pr' is 'PRAY'.
(Other definitions for pray that I've seen before include "make supplications" , "Appeal to higher authority" , "Wish earnestly (for a particular outcome)" , "Devoutly hope" , "follow religious practice" .)