You can move a page from one menu to another. For example, you can move a page from the main menu to the secondary menu.
From the Dashboard (admin/dashboard), click Manage Links next to the menu you would like to move an item from (such as the Main menu). Find the link you would like to move (such as "News"), then click "Edit".
From "Parent Link," find the menu you would like to move the item to (such as Secondary menu), then click Save.
Once the item has been moved to the desired menu (such as the Secondary menu), you can re-order the items in the Secondary menu by clicking "Manage Links" next to the menu and dragging and dropping the item in the correct spot. See Reorder and Manage Menu Items.