She finishes her monologue by saying that she is going to "chastise with the valour of my tongue "(Shakespeare, Act 1 Scene 5 Line 25 ) saying that she is going to nag him until he works up the courage to kill King Duncan. Lady Macbeth realizing that her husband cannot get the job done she "consciously attempts to reject her feminine sensibility and adopt a male mentality"(Asp,153) so that she can muster up the courage and the will power to kill King Duncan. Lady Macbeth calls upon the spirits and asks them to "unsex me here, And fill me from the crown to the toe top-full Of direst cruelty!"(Shakespeare, Act 1 Scene 5 Line 40). Lady Macbeth goes so far as to tell Macbeth that he "look so green and pale"(Shakespeare, Act 1 Scene 7 Line 37) which would mean that he looks like he has anemia which was thought back then to mean that you were a virgin girl if you got the green sickness. Lady Macbeth is so bold and dominant in the relationship to say that he looks like a virgin girl because he does not want to kill King Duncan. Lady Macbeth ultimately adopts the "physical/psychological states that are fundamentally associated with the sexual stereotypes in the play"(Asp, 160) and does every job leading up to killing King Duncan which she forces Macbeth to do. Lady Macbeth plays the man in their relationship by ordering Macbeth around and calling him very rude names all in the interest of him being King.
One of the less obvious examples of gender reversal/breaking would be the witches. Shakespeare created them with this story to "perverse variants of femininity, disrupt the natural order of Macbeth's world and create a realm of error and mutability."(Brinzeu, 256) A more noticeable example of how they are breaking gender roles is society is how when Banquo first meets them he know that they are women but, "And yet your, beards forbid me to interpret that you are so"(Shakespeare, Act 1 Scene 1 Line 46) which also means that the witches generally look manly.