Unfortunately you won't be able to parlay a non-refundable voucher into a refundable voucher in that manner.

Also, be very careful with your proposed scheme; there is a danger that, at the time you come to cancel this flight, there will no longer be any waivers in place and you will immediately lose the value of the booking.

It's not recommendable to book travel for a date well in the future for which you have no intention of travelling - at least book a date that, if push comes to shove, you may actually be able to travel on (if only because the alternative is to lose all value of the ticket) - particularly as the original voucher did not need to be used for another almost 9 months!