Full context:   The president may not dissolve Congress, but has the power to adjourn Congress whenever the House and Senate cannot agree when to adjourn; no president has ever used this power. The president also has the constitutional power to, "on extraordinary Occasions, convene both Houses, or either of them"; this power has been used "to consider nominations, war, and emergency legislation." This Section invests the President with the discretion to convene Congress on "extraordinary occasions"; this special session power that has been used to call the chambers to consider urgent matters.