Concerning summons - number corrected (9)
I believe the answer is:
rewritten
'corrected' is the definition.
The definition and answer can be both to do with communicating as well as being past participle verbs.
Maybe there's an association between them I don't understand?
'concerning summons number' is the wordplay.
'concerning' becomes 're' (both can mean on a particular topic).
'summons' becomes 'writ' (I've seen this before).
'number' becomes 'ten' (ten is a kind of number).
're'+'writ'+'ten'='REWRITTEN'
Can you help me to learn more?
(Other definitions for rewritten that I've seen before include "replaced in different form" , "Again put down" .)