Yes, you can book Star Alliance Rewards, using Aeroplan miles, through the Aeroplan DESK-- not the website. There's no waitlisting allowed and the flights on partner airlines are NOT changeable unless you return the ticket, pay the fees and REBOOK. The seats alloted by other airlines are very limited. e.g. on a SQ flight there were no seats but when I was on a Revenue ticket on J class, I was the only passenger!! So who used the reward seats??