I’m not a CBA customer, but most banks would much rather keep you than lose you, so if you tell them you intend to leave, and then give them a specific reason why (i.e. annual fee, point earn is rubbish) they will often try and remedy this by waiving or offering bonus points. Using specific keywords like “cancel” may also trigger a transfer to the Retentions department who have more power to make you an offer you can’t refuse.
Worth looking at this article (there are some good tips in there), but there isn’t any mention of CBA in it. Maybe update Keith with your experiences after you call.
Just remember to be reasonable and polite, and be prepared to close the card if they don’t offer you something you’re willing to accept.