In some U.S. states and other jurisdictions, it is possible to grant a "springing power of attorney"; i.e., a power that takes effect only after the incapacity of the grantor or some other definite future act or circumstance. After such incapacitation the power is identical to a durable power, but cannot be invoked before the incapacity. This power may be used to allow a spouse or family member to manage the grantor's affairs in case illness or injury makes the grantor unable to act. If a "springing" power is used, the grantor should specify exactly how and when the power "springs" into effect. As the result of privacy legislation in the U.S., medical doctors will often not reveal information relating to capacity of the principal unless the power of attorney specifically authorizes them to do so.