In a publishing SharePoint site, any page you add or create is based of a layout. Layouts are the templates that define how a page looks and where the content can be added. These layouts in SharePoint are broadly classified into two categories – article pages and welcome pages, and any custom layouts can be added.
There are many a times when we create a page, add our webparts and content only to realize that we need something extra, something different, a different look 
. We want to use a 3 column layout instead of a 2 column page layout or even a custom built layout. {I will discuss in my later blogs on some easier approaches to create a page layout.}
To change a page layout from the browser, here are the steps to follow
- Edit the page by going to Site Actions and Edit Page.
- From the edit page menu that appears on the top of the page when in edit mode, click on the page menu and select “page settings and schedule”.
- In the page settings page, you will find a section for Page layouts where you can select the layout required from list of layouts available in the dropdown.
- Click ok and notice the layout changed.
Be careful when doing this if the webpart zones between the two layouts doesn’t match. SharePoint is smart only to retain the content if the name of the zones match when layouts change . Else the data is lost. So either move all the content to one zone that exists and then move across the zones or save the content some place. Something I have learnt the hard way.
Good Luck.
