A commercial sublease is an agreement to lease space from a tenant rather than directly from a property owner. Find Your Next Sublease.View currently available sublease space in the Chicago market. In Chicago, landlords must approve reasonable sublease requests unless the property is owneroccupied with six or fewer units. Subleasing commercial property can help you mitigate the cost of your lease if you no longer need or can't afford the space. A commercial sublease agreement is a statutory document authorizing a third party to occupy a leased property under the original lease agreement. Fill Out Form to Contact Chicagoland Commercial Today! Can I Sublease My Space? Plus, explore the insight and resources available in the Chicago REALTOR® Magazine digital issues. Find your next opportunity on the world's leading commercial real estate services and investment team.