As others have noted, having an MDR dinner sent to a stateroom can be an option if exceptional circumstances [usually involving illness] are involved, and it really has to be something that is offered at the discretion of the dining staff when they think the circumstances warrant it, as opposed to asked for.
I had an allergic reaction one night in the MDR [airborne reaction to seafood] just before our main course started. I had to rapidly leave the MDR.
Our serving team packaged up the rest of my dinner for me. The Head Server called to check on me later that evening.
The Head Server explained that in two nights time it was Lobster Night and he suggested I NOT eat in the MDR that night as "lobster is everywhere" and it would be even worse than that night, that instead if I was ok with it they would bring my dinner to my stateroom on Lobster Night. We already were used to ordering our meals the night before because of food allergies, so this was easy to manage; we pre-ordered at dinner the night before. On Lobster night someone from the serving staff from our assigned MDR [not our serving team but they had the uniform from that MDR on] brought my pre-arranged meal to my stateroom at the time we had arranged with our Head Server. It came with a nice note from our Server and Head Server. My sister had dinner alone in the MDR [it was Animator's and she wanted to see the show!].