What is the outcome for J and M after H conveys his interest to W, given they are joint tenants?

When H conveys his interest to W in a situation where J and M are joint tenants with H, the fundamental principle at play is the nature of joint tenancy and its rights of survivorship. In a joint tenancy, all tenants have an equal share in the property and if one joint tenant transfers their interest, it severs the joint tenancy and typically converts the ownership into a tenancy in common with the new party.

In this scenario, because H is transferring his interest and not J or M, J and M will not lose their joint tenancy status with respect to each other. Instead, they remain joint tenants owning their two-thirds interest in the property. H's conveyance does not affect J and M's ownership, and thus, they retain their rights and connection as joint tenants with shared ownership of the property, but with a reduced interest because one joint tenant's share has been conveyed to W.

This situation results in J and M owning two-thirds of the property as joint tenants while W becomes a new single owner of H's conveyed one-third interest, breaking the joint tenancy between H and J & M. Hence, they maintain their status as joint tenants with a two-thirds interest in the property.