Hi 747-444 - the difference between this and your original post is the type of ticket. A domestic flight, point to point with the one carrier puts the issue of compensation with a single person. With a DONE ticket, several carriers will be involved and each is looking for their piece of the money.

There is no reason why the airline which downgrades you can't give you a voucher. Compensation would be negotiable.

Forgot to mention in my original post that special rules apply to EU flights and EU carriers - if you are involuntarily downgraded on one of those, then you will be entitled to significant compensation provided the reason for the downgrade is within the control of the airline.

Regards

lme ff