Unfortunately, this is why DL provides specific warnings about BE and then makes you check a box stating that you understand the specific BE restrictions. The ticket is inflexible. If not flown as ticketed, it is cancelled and retains no value.
You mentioned "meetings". Presuming that you have an employer paying for your travel, in the ordinary course, making this right is a cost carried by the employer. Unless your travel insurance is "all perils" it is unlikely to cover a change in work-related meetings.
Some of the suggestions above make sense, especially those which may be inconvenient but get you back to SEA in time to catch your new outbound. A miserable series of flights, but a solution.