Are you sure, Andy? I'm not sure about it.

Not sure I understand, do you mean the domain, I thought the new title would be part of the URL

That is the reason for the follow up question

If you change the URL or portion after your domain it's like moving to a new house and starting over. You have to send out a change of address to the post office and to important places like your bank, your accountant, your work, etc..

As a result, Google will not know where to find the post for some time and thus the ranking will drop from that post, your site will be penalized for the broken link, and all the inbound links from other sites will no longer be valid. The new post location may not make it back to the rank your old location was because of this.

By changing the name of the post and it's description though you can improve SEO without changing the URL. This can allow you to improve rankings without moving to a new home. Just to note I am a search junkie having even co-owned my own search engine and social media hybrid for 9 years, this is a common practice in Search Engine optimization.

I have some posts that I changed the title. When I changed it I should change the permalink also because permalink includes the title, and I should change also the Description and the keyword.

Don't change the permalink, it has less to do with the ranking of the page than you think unless you turn a permalink into a permanent set of 404 Page Not Found errors stretching around every search engine and linking page.

A permalink is like a business address, you can change the business there or put up a new sign and describe the business as something else but you can't change the address without a headache.

I did to some of my posts. I only don't know what is happening since I did not receive a report of 404.

if you changed the URL and went to the old one you would get the 404 error message

Thank you .i am about to make some changes and thought I should revisit.