A developer must notify you of any material changes in the information and documents that it provides to you. The developer must provide you with a written notice within a reasonable time after the change occurs and before you take possession of the unit. A material change is a change in the developer’s information or documents that would have a negative effect on the value/use of your unit or the corporation’s common or real property.  Seek legal advice if you have a dispute with your developer over any changes that arise during construction.