How to Change Edit Account Information Layout in Magento

Default page template for product description page:

Add this to your <layout> in local.xml:

<catalog_category_default translate="label">
     <reference name="root">
         <action method="setTemplate"><template>page/2columns-left.phtml</template></action>
     </reference>
   </catalog_category_default>

For CMS pages this can be done from the backend.

From

Cms > Pages > Home > Design > Layout

Add the tag to the root of the page in the layout xml

<catalog_product_view>
    <reference name="root">
        <action method="setTemplate"><template>page/2columns-left.phtml</template></action>
    </reference>
</catalog_product_view>

For more info this LINK can be a help.

It seems you are using a theme. It might have it's own XML to define layouts or not, since i dont know the theme i cant tell you. But the most normal way to do this is to open customer.xml in the layout folder of your theme and find the path to the My account page (customer_account_index) and change your layout from there. See this, it is very similar to your question and might help you.