Originally Posted by LHR/MEL/Europe FF

Unfortunately not. Lifemiles tickets you can't change class of service.

The option you will have is to either (a) fly in the lower class, no refund of points of (b) cancel the ticket free of charge, get all your miles back, and rebook into business class at the lower price.

However... if there are no award seats in biz class you may end up with no flights at all