How long does my landlord have to change my locks?
After you have provided proper notice to your landlord, your landlord must change the locks in two days or give you permission to change them. If your landlord does not change the locks or give you permission within 48 hours, then you are allowed to change your locks without your landlord’s permission. If you change your own locks, you must make a good faith effort to give your landlord a copy of the new key.*
* 765 ILCS 750/20(b)