A person may be both a general partner and a limited partner in a limited partnership if his interests are separately designated in the partnership agreement. A person who is both a general partner and a limited partner has the rights and powers and is subject to the restrictions and liabilities of a general partner and, except as provided in the partnership agreement, also has the rights and powers and is subject to the restrictions and liabilities, if any, of a limited partner to the extent of his participation in the partnership as a limited partner.