wordpress rewrite and google SEO issue

I have a custom wordpress page that I wanted to make its url SEO friendly.

So I added some code using rewrite api to convert this url:

http://ift.tt/1AF3qeT to: http://ift.tt/1AmByqR

page1 is still there and first url still valid. page1 was not very descriptive so I though that since I'm rewriting the url I might as well rename the page too.

Everything on the website works fine, but when I recreated the sitmap xml file and resubmitted to google I was hoping google would forget the old url and start showing the new one. This was a few weeks ago and I'm still seeing old urls. Any idea how I can remove the old urls? Do I need to physically rename the page itself?

Please help.

Thanks