Sorry, I only bet on very rare occasions so I'm clueless about the whole process. I don't have an online account, I just bet via the physical kiosk. I'll scour their website again to see if I can find out. Thanks for the response.
Assuming by physical kiosk you mean TAB. Bet will be cancelled: https://help.tab.com.au/s/article/A-meeting-is-postponed-and-then-set-for-another-date