If you claim an exemption, then stop using the property as a principal residence, you must notify the Township Assessor within 90 days of the change or you may be penalized. This can be done using the Form 2602 (PDF) request to rescind homeowner’s principal residence exemption.
A conditional rescission allows an owner to receive a principal residence exemption (pre) on his or her current property and on previously exempted property simultaneously if the previous principal residence (all must apply): is not occupied, is for sale, is not leased, is not used for any business or commercial purpose.
In general, an owner may receive the PRE on the previous principal residence for up to three years if the conditions above are met. The owner must annually submit Form 4640 on or before May 1 in the initial year and December 31 thereafter. Only the owner who previously occupied the property as his or her principal residence qualifies for the conditional rescission. Conditional rescissions are not retroactive. At this time the July and December Boards of review do not have jurisdiction over them to make changes if you miss the filing deadline.