This just highlights the need to check your flights on a regular basis, especially if you booked them very far in advance. Airplane loads change and more often that you may realize, airlines will change out aircraft types on you. When I originally booked my flights, I had purposfully booked a Virgin Atlantic flight on an A340, since I've never flown that aircraft. That plane also was changed out for an A330-300, which I've flown many times out of Philadelphia since US Airways and subsequently American Airlines flies these almost exclusively out of Philly to Europe.
My original booking with Emirates took place when they first announced a second daily A380 flight between Dubai and LA. Passenger loads don't always live up to expectations though, and at some point without my knowledge, the plane was changed to a smaller 777-300ER. Don't get me wrong, any other trip after this, I might actually prefer the 777-300ER. The 777 first class cabin is much smaller and would likely be very enjoyable. However, Emirates 777 aircraft do not feature the onboard shower of the A380, and I very much want to enjoy that part of the Emirates experience. I booked this flight specifically for the aircraft... so what can you do?
Your mileage may vary here, since this is an award flight, lack of space on another flight may be an issue. There may not be anything you can do, but I highly suggest you try to call the company you booked through. In my case this was Alaska Airlines, and as always the phone agent was perfect, why Alaska Airlines excels where other airlines fail miserably is beyond me, but they can keep up the amazing service, I will never complain about that.
As soon as I had an agent on the phone from Alaska Airlines, I explained the situation and she went to work. I informed her that there is an earlier flight from Dubai to LAX that is indeed still the original A380 aircraft. A quick search showed her that no open award seats were available for her to book me into. This didn't deter her though, she put me on hold for quite a while, but I knew what she was up to. She contacted Emirates directly and asked them to open a seat for her to put me in.... they obliged.
She came back on the line, asked me to back out of the website while she made an update, and within a few minutes I was booked on the earlier flight and back on an A380. Can I just say this Alaska Airlines... you are awesome! No fuss, no hassle, they just took care of it for me. What a great experience.
As for the other flight that was changed on me, my Virgin Atlantic flight was booked though Delta. I imagine it would be much more difficult for me to change that flight. For one, there is only one daily flight on Virgin Atlantic out of Atlanta, so no other flight to put me on. Also, I'm not sure I'd want to change this flight. This puts me on the newest Upper Class product from Virgin Atlantic, and would likely be more relevant to you readers, since the A340 is on its way out and the A330 is the latest. If I do decide to change things around, I'd likely have to change airlines, which might or might not be worth it. I'll look at it, but I don't anticipate making a change to this flight. If I do, I'll update everyone once that happens.
For now, the moral of the story is, if an airline changes equipment on you, try to get them to move you around. It may surprise you that they might just be willing to accommodate you, no questions asked.... though they may not as well. I had a great experience and cannot thank both Alaska Airlines and Emirates enough.