Wordpress: I Removed Parent Slug from URL but word

Question

I have successfully removed the parent slug from URL and have reduced the URL from:

http://myexp.uphero.com/sample-page/child-sample-page/

to

http://myexp.uphero.com/child-sample-pagee/

This is a test wordpress website for testing purposes. But when I visit the newly reduced URL, the old URL (with parent slug) appears again in the browser's URL bar. Please help me, why this it is including the parent slug again in the URL? I have search around the web but didn't find solution. Also, I have written the following rewrite rule for the reduced URL

^child-sample-pagee/?$' => '/index.php?pagename=child-sample-page'

The rewrite rule also works well, without any problem. Just visit the above newly created reduced link, and you will see the actual problem. Waiting for response and solution.