Help when ready (5)
I believe the answer is:
asset
'help' is the definition.
(an asset can be a help)
'when ready' is the wordplay.
'when' becomes 'as'.
'ready' becomes 'set' ('set' can be similar in meaning to 'ready').
'as'+'set'='ASSET'
(Other definitions for asset that I've seen before include "Anything of value" , "Something that's worth having" , "Strong point" , "Item well worth having" , "Plus point" .)