Commercial realtors work with sub-lessors to find a suitable sub-tenant and negotiate sublease terms. In New York, tenants who wish to sublet their commercial lease must obtain written consent from their landlord.The first step in subleasing office space is to determine how much space your business needs both today and as far out in time as you could reasonably forecast. Subletting your office space or commercial property? Easily customize your own Commercial Sublease Agreement. See: Lease Renewal, Lease Assignment. Questions? Fill out the form below to speak with a commercial real estate loan specialist. When deciding whether to sublease space, a subtenant should first analyze the master lease. Bar of the City of New York. To properly sublet your office space, you need to have a detailed understanding of how the process works.