7.1 does not have a design tab under pages, and 7.1 does not have a change template option as well, because all the templates in 7.1 are in actuality one template, and using font and color palette changes, any one of the 7.1 "templates" with a bit of work, can be made to look like any other. When you add a page under navigation, you will see many options including page layout. When editing a page or a section of a page, you will see a menu block on the right which includes, depending on the page the option for layout or new layout. In most cases changing a 7.1 template to look like another can be easier than changing from one 7.0 template to another.
