What to Do with My AmEx $450 Qantas Credit if I Don't Have Specific Travel Plans?

I have a Qantas American Express Ultimate Card which I am looking at downgrading or cancelling. However, this will mean I lose the $450 credit with Qantas that the card carries. I don't have any particular travel plans at the moment; is there any way people would recommend I use this credit? Can I put it towards a flight or hotel and then later change the date? Any suggestions would be appreciated.