Click the 'Move Stand Wall' button which is located on the HOME ribbon then hover over the wall you want to move, a little circle with a cross will appear as shown below, when it does click your mouse button to start moving the wall.
TIP: You can also initiate this function by using the default Hot Key ' W '
Move you mouse left or right to the desired position (the dimensions will turn Red while doing this so you can see the required size more easily), and then click to position your wall: