It may be worth waiting for them to cancel it for you. They just sent me an email telling me that my June flights just got cancelled and the email directed me to a form to request a refund of my miles and booking fees and said there would be no redeposit fees.
"If you had redeemed your ticket using miles or have a Mix KrisFlyer Miles and Cash booking, the miles will be refunded to the KrisFlyer account where they were deducted from, and the cash to the original mode of payment. Any associated fees will be waived."