The blocks within a page layout can be switched around at any time to rearrange your content.

To change which section the contents of a block will fill, select the Manage button at the top right of the block you want to move, then select Move:

A new window will appear with a basic representation of your page layout, with the currently selected block highlighted in yellow. Select any blocks to move the currently selected block in its place (once selected, the block you are moving the selected one to will turn green). Select Move to complete the move.