Once a property is designated by bylaw, the owner must obtain a Heritage Alteration Permit to make alterations to specific exterior (and possibly interior features) that are listed as significant in the designating bylaw. Designation is generally limited to the building exterior and even then does not prevent all changes forever. For example, if the streetscape was noted as being significant, a Heritage Alteration Permit would be required for alterations to the parts of the building visible from the street (i.e. the front door), but may not be required for alterations that wouldn’t be seen from the street (i.e. any rear windows). A Heritage Alteration Permit is often required to make changes to a property within a Heritage Conservation Area.