In early September, you'll receive mail from the company secretary advising of what date the options will be removed from trading on the ASX. It's not necessarily 2 days before expiry from my experience.
Conversion forms will be included with instructions on how to send the money (cheque or electronic).
Watch the demand for options in the weeks before to determine how comfortable you are that you'll get a good price for the ones you sell.
APC Price at posting:
13.0¢ Sentiment: Buy Disclosure: Held