I logged onto my inreach.garmin.com account today to see what state I had left it in after last year's hiking season, and of course the three preset messages were all about last year's last trip. So I figured I'd just delete them to clean things up for this year. Hmmm... no "delete" button! That seemed ridiculous to me, so I surfed all over the place looking for what I might be dong wrong, but after coming up empty-handed it suddenly dawned on me that since there are always exactly 3 preset messages, perhaps there's no need to able to delete them; maybe Garmin just expects me to modify them when appropriate. Is this correct, or am I missing something fundamental?
Don't think you are missing anything - just edit content (and address(es)) at Messages>Preset Messages>Edit on your inreach page. As you say, you have three "envelopes" whether you want them or not - up to you what you put in them.