Permalinks in wordpress

I know, we can change the permalink structure of a wordpress blog "posts" via the options.
But is there a way to change permalinks for "pages" as well? I don't seem to find

For e.g a "page" is http://xxxxxx.com/blog/first-page/

Now I want this to be http://xxxxxx.com/blog/first-page.html

I know how to do it with "posts" but not with "pages"

Thanks for your help.

 

use this %postname%.html

 

I need the "page" to be like that not the "post".

 

ah sorry, my bad. Not read it properly