Simply suggest the idea, with the framing of 'honouring democratic will, that right to self-determination itself that Theresa feels qualified to lead a policy she was against because of her firm belief in, and the desire for a peace based on recognizing the mixed heritages of the people of Northern Ireland by allowing them to retain a connection to a part of Scotland'.
Why is this important?
It would allow for a peaceful resolution if May was actually willing to agree to it, and even if (or I suspect when) it was rejected out of hand it would do good for the relationship between reasonable Ulster Unionist political factions and our Republic.