Louisiana constitution
Article 3
Section 18

(1) A bill vetoed and returned and subsequently approved by two-thirds of the elected members of each house shall become law. The legislature shall meet in veto session in the state capital at noon on the fortieth day following final adjournment of the most recent session, to consider all bills vetoed by the governor. If the fortieth day falls on Sunday, the session shall convene at noon on the succeeding Monday. No veto session shall exceed five calendar days, and any veto session may be finally adjourned prior to the end of the fifth day upon a vote of two-thirds of the elected members of each house.
(2) No veto session shall be held if a majority of the elected members of either house declare in writing that a veto session is unnecessary. The declaration must be received by the presiding officer of the respective houses at least five days prior to the day on which the veto session is to convene.