Intervening rights apply to reinstated patents during a specific time frame. According to MPEP § 2591, these rights are applicable to actions taken: After the 6-month grace period for paying the maintenance fee But prior to the acceptance of the late maintenance fee The MPEP states: "A court before which such matter is in question may provide for the continued manufacture, use, importation, or sale of the thing made, purchased, imported, or used as specified, or for the manufacture, use, importation, or sale of which substantial preparation was made after the 6-month grace period but before the acceptance of the late maintenance fee." This timing is crucial for determining whether intervening rights can be claimed and to what extent they may be granted by a court. To learn more: intervening rights reinstated patents maintenance fees grace period patent lapse