Hi Minnie Mum,
I'm not sure if that is the complete answer. (And if I already knew the answer, I wouldn't have asked.) Are you telling me what you know to be true (like from direct experience or because you work there), or just what you
believe to be true?
My preference is for all 8 of us to go. It is only by coincidence that I happened to check to see if ADRs for 4 were available. But what if we had booked an ADR for 8 months ago, when there were both ADRS for 4 and ADRs for 8 available? Would the cancellation policy be different then? Are you saying you know to be true that if my friend isn't able to make it I will be forced to cancel for everyone - not just the parties that aren't able to come?
Thanks to you (and anyone else) for any help in finding the actual policy.
Whoa!

Dude what's with the attitude?

People just trying to help people, you know?
As a matter of fact I do know this from experience. However, I'm sorry that I cannot quote chapter and verse from Disney's policy books since i do not work for them

. Just a fan who has been going regularly since 1975.
It doesn't really matter how long ago you made your ADR and whether or not ADRs for 4 were available then. What matters is whether you made a single reservation for 8 or 2 reservations for 4. If the latter, then cancel one and you're fine. If the former, and AT THE TIME YOU CANCEL there is no availability for a party of 4, then you have a problem.
Another thought: is there perhaps availability at another show that night, or could you switch to another night during your stay?
It is always possible that you could just show up and throw yourself at their feet, begging for mercy. You never know. Disney is nothing if not accommodating.(sorry, I can't swear that this is in fact Disney policy) All I was saying in my previous post was (based on the wording of your initial post), you
cannot partially cancel an ADR You either cancel it and make a new one, or you don't cancel.
If you want the official written Disney policy, then you would have to contact Disney directly. No point in asking a DISCUSSION board for that.