If the landlord is willing to substitute a new tenant in place of an existing tenant under the lease presently in effect then the new tenant would end up taking over the balnce of the lease.However, to make sure there are no problems in the future, the landlord would need to specifically release the old tenant from the lease in writing and expressly allow the new tenant to take over the lease.A cleaner way of doing the transaction would be to end the existing lease with the tenant for the property being rented in a document signed by the landlord and that teant and have a whole new lease entered into with the new tenant and landlord memorialized in a written document.The new lease with the second tenant can have a longer term than what was remaining on the lease presently in effect concerning your question.