Used wordpress built-in permalink to change post url but the page is not found

Question

You just need to ensure that it’s written to your .htaccess file in the root of your website.

If not, it didn’t work when you saved it.

It should contain something like:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress