Most of the lease (residential tenancy agreement) is made up of standard terms that have been taken from the Residential Tenancies Act (NT). They cannot be changed or deleted. However, you as the tenant or the landlord can add additional terms to the lease as long as these terms do not contradict the Act.:

One common additional term added by the landlord is that no pets are allowed. If you intend to get a pet or already have one, then ask the landlord's permission to keep the animal(s) before you sign the lease and have it mentioned as an additional term.