We got our DD to comply with work she found beneath her by letting her know how it was in her best interests. We know who she is and what she can do because we see her every day, but these people don't know her or her capabilities, stories are easily disbelieved, but if she shows them what she can do, they can't argue with the evidence.
Then we backed up our words with actions, because when the school refused to cooperate with our very reasonable request for a full grade acceleration (which we'd already been making for two years, and had given their half-baked alternatives a full chance) we yanked her out of public school as a 2nd grader, homeschooled her for the rest of the year, then had her sit the state's end-of-third grade standardized achievement test. Then we went back to the same school the next year, declared her having mastered third grade material, showed them the test scores that proved it beyond all doubt.
