Support a right to begin afresh (7)
I believe the answer is:
restart
'begin afresh' is the definition.
(I've seen this before)
'support a right' is the wordplay.
'support' becomes 'rest' (e.g. a shoulder rest is a support for shoulder).
'right' becomes 'rt' (abbreviation as in Rt Hon- the Right Honourable).
'rest'+'a'+'rt'='RESTART'
'to' acts as a link.
(Other definitions for restart that I've seen before include "Begin anew" , "launch again" , "Jumping the gun will mean" , "Resume" , "begin afresh" .)