This excerpt taken from the MRO DEF 14A filed Mar 13, 2007.
12. Option Exercise. The Grant Price shall be paid in full at the time of exercise in cash or, if elected by the Participant, the Participant may purchase such shares by means of tendering Common Stock or surrendering another Award, including Restricted Stock, valued at Fair Market Value on the date of exercise, or any combination thereof. The Committee shall determine acceptable methods for Participants to tender Common Stock or other Awards; provided that any Common Stock that is or was the subject of an Award may be so tendered only if it has been held by the Participant for at least six months. The Committee may provide for procedures to permit the exercise or purchase of such Awards by use of the proceeds to be received from the sale of Common Stock issuable pursuant to an Award (including cashless exercise). Unless otherwise provided in the applicable Award Agreement, in the event shares of Restricted Stock are tendered as consideration for the exercise of an Option, a number of the shares issued upon the exercise of the Option, equal to the number of shares of Restricted Stock used as consideration thereof, shall be subject to the same restrictions as the Restricted Stock so submitted as well as any additional restrictions that may be imposed by the Committee. The Committee may adopt additional rules and procedures regarding the exercise of Options from time to time, provided that such rules and procedures are not inconsistent with the provisions of this paragraph.