Originally Posted by Guava

I believe it would work if my memory is correct. The breakfast restaurant at Copley Plaza Fairmont is technically a 3rd party restaurant, but I believe you can charge it to your room. Because of that, you should be able to use your dinning certificate. But if you are not actually staying at the Copley Plaza, you may have to ask the front desk to set up a temporary room number for you so that you can charge it as if it's a room charge.