When changing a room, where do I make the changes (myallocator, or the channel)?

Answer:

When setting up rooms within myallocator, the rooms must be created so that they "match" or "mirror" the rooms on all of your systems (PMS, myallocator, OTA).

Room changes in myallocator do not push to your channels.  All rooms in myallocator must simply mirror what is already set in the channel.

If you make any room changes in a channel, those room changes will only be updated in the channel extranet.  After the changes are made in the channel, you must also make the associated changes within myallocator.  Once the rooms have been updated in myallocator, you must then then redo the channel setup for that channel within myallocator.  

For full instructions on how to make room changes across all of your systems (PMS,myallocator, OTAs) please see this article:  

Adding or changing a room in your property

Note:  

You will also need to update the rooms on your other channel extranets as well, otherwise the rooms will be setup differently between each channel which will cause issues.

Summary:

In short, the myallocator rooms simply need to "mirror" or "match" the room setup in your channel extranets, and the rooms should all be setup the same everywhere.