Subleasing is the practice where an existing tenant rents out part or all of their leased commercial space to a third party known as the subtenant. Simply call (214) 272-2111 and ask to speak to one of our brokers.A sublease, or sublet, occurs when a tenant assigns part or all of their lease to a new tenant. In general, most commercial leases permit subletting. A sublease, or sublet, occurs when a tenant assigns part or all of their lease to a new tenant. In general, most commercial leases permit subletting. Commercial real estate in the United States is set for a transformative 2025. If Subtenant will pay additional rent based on increases in real estate taxes, check here __ and complete Section 1.14. 1 and 1.14.2. 1.14.1. Sublease. Colliers is a leading diversified professional services and investment management company.