I have renamed my old URL but google is showing "Duplicate, submitted URL not selected as canonical"

I have recently renamed my website pages URL and now when I submit my new sitemap google is not indexing my new URL it is showing "duplicate, submitted URL not selected as canonical". It is still showing old URL in google search so I block the old URL using google webmaster. How to solve this issue how to index my new renamed URL and also how to remove old URL from google index ?