A lessee who is prohibited from assigning his/her lease will pay a lower rent as compensation for that restriction. Assignment may be subject to the lessor's consent that cannot be “unreasonably" withheld (for example, under the Conveyancing Act (NSW) and Landlord & Tenant Act (SA)). The lessee otherwise is forced to surrender the lease if he/she assigns it.
Assignment is usually evidenced by a deed of assignment that may not be registered even if the lease is registered. If the lessor is party to the deed, the terms and conditions of the lease may be varied at the time of the assignment and such variation will affect the value of the lease. For example, the new lessee in negotiating a second option to renew may agree to a rent increase or more regular rent reviews. It is often very difficult for the valuer to find out about such lease variations.