Dear Middletown Tenant:
Your roommate being lazy is not a different story. Tenants who sign a lease with a landlord as co-tenants take on joint as well as independent responsibility for the tenant lease obligations. That means each tenant for the duration of the lease shares paying rent with the co-tenant as well as full liability to pay rent on her own. If you pack and go, while you remain liable to the landlord, the reality is the co-tenant will need to pay the rent for the remainder of the lease. New York State law allows your co-tenant the right to replace you with a roommate to help her pay rent (the law even allows passing the entire rent over to the roommate to share the apartment; but that does require a very generous roommate.) Your problem is that your co-tenant is lazy and so will not find a replacement for you when you go, so you should find the roommate on your own. The roommate will need to be more tolerant than you of your friend's attitude to life.
Usually, tenants do not move into a new home without the landlord delivering a copy of the lease and handing over the keys. Perhaps your co-tenant has the lease.
In any case, if neither tenant received the lease then perhaps you could both hire a lawyer to convince the landlord to let you both go. If not, then you and your co-tenant will need to discuss your desire to move out and her right to a roommate to replace you.
