Protocol – Mtgs at work

At my job, I often have mtgs canceled/rescheduled/or pulled into mtgs unexpectedly throughout the day. In fact, just now my boss rescheduled our mtg to 12pm, which I had scheduled for myself to eat lunch. I have learned to keep my schedule flexible to adjust to these unexpected changes, but now I’m not sure how to translate that with my protocol. Is it fine to move my meal times the day-of when something affects my protocol like this?