Without it, the sublease might not be valid. This consent can be obtained through the original lease agreement or a separately signed document.Doing this without written consent of the property owner will get you evicted. Just as quick as not paying rent (a fast and easy eviction case). Your landlord cannot unreasonably withhold consent to sublease. Subtenant agree that the Sublease shall not be modified without Landlord's prior written consent, which consent shall not be unreasonably withheld. Here is a sample sublease agreement you can fill out or use as a template. Need to sublease your rented apartment? Here's why you should obtain your landlord's consent first.