I wouldn`t mix 1 brand of monomer with another brand of powder but when doing infills or I prefer to call it rebalancing, lol, then I get the client to sign a disclaimer in case of problems. The only enhancement I won`t do any work over is the dreaded MMA which you can usually see at a glance or once you take a file to it, pooh!!!!!!!
I then give them some info and advise them to have them taken off and start again.
The answer is 'yes' you can rebalance this client with CND but depending on what has been used, you will almost definitley see a difference in clarity!! BTW I personally never used to R/B others work (unless I knew them) - if the dreaded greenies appeared :alien: I would be blamed (even it had been due to prevous contamination)!! Just a thought