When King Duncan arrives at Inverness Castle, Lady Macbeth greets the king in an unctuous, ingratiating manner.
All our service,In every point twice done and then done double,Were poor and single business to contendAgainst those honors deep and broad wherewithYour majesty loads our house. (1.6.14-18)
Lady Macbeth, in act one (scene six) of William Shakespeare's Macbeth, welcomes King Duncan into their (Macbeth's and her) home. She is overly welcoming. She states that everything has been double checked and double checked again in order to insure everything is in order for the king's visit. Duncan calls Lady Macbeth an honored hostess, and she proves to be very honorable (at least to his face).
Lady Macbeth most likely greets the king by herself because Macbeth is most likely contemplating the murder of Duncan. Later, she will take Duncan to meet Macbeth (probably as what would be custom in the times).