Air New Zealand Air Points - Booking then cancelling Airpoints tickets

I have a number of Airpoints that will expire in a few weeks. I don't have a definite trip in mind for them yet so I was thinking of booking a trip with dates six months out before they expire. Then I plan to cancel the reservation and replace it with something definite in a few months time once I have finalised my plans.

Am I allowed to do this? Will I lose any points or have to pay any extra charges? Can I completely change the itinerary?

Thanks in advance for any advice.

There shouldn't be a problem. You wont be able to book the trip, then cancel it and have your points back (with a new expiry date) but you can just pay the $50 fee and make changes to your original booking. They may try and prevent you from changing the booked ticket for flights beyond 330 days after the points were due to expire, but if you arent trying to push the envelope that far, you shouldnt have too many problems.

The airpoints staff in CHC are pretty good but to keep things as simple as possible I would try to book a routing the first time around as similar as possible as to what you ultimately hope to book and take.