Can I claim for my business travel?

I submitted my tax return and answered yes to having a logbook, I however cant locate it right now and was wondering if I can resubmit my return and just click the No option on the logbook question instead of yes?

Yes you can resubmit your tax return and just change the Yes for logbook to No instead.

Thanks for your reply. Instead of changing to "No", can I keep the logbook as "Yes" but change the mileage? My computer was stolen with all info on and I tried estimating my mileage, I have since found my mileage and my initial estimate was wrong.

Yes you will be required to submit a logbook and yes are able to resubmit your tax return and correct the actual mileage you travelled.
In the supporting documents just attach a letter explaining that you estimated the expense but have since found your logbook.