Checks altered, possibly to prepare for a new start (5,3,5)
I believe the answer is:
clear the decks
'prepare for a new start' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'checks altered possibly' is the wordplay.
'possibly' indicates anagramming the letters.
'checks'+'altered'='checksaltered'
'checksaltered' is an anagram of 'CLEAR THE DECKS'.
'to' is the link.
Can you help me to learn more?
(Other definitions for clear the decks that I've seen before include "tidy up after game of rummy" , "Prepare for action - these crackled (anag)" , "prepare for new action" , "Tidy up all suits on hand to" , "Get ready for action" .)