Why does it keep the same name, even if I change the "save as" to a different one?

Hi!

I hope you are doing well.

If you wish to keep the Filename and the Document title, you can enable the preferences settings in Acrobat/Acrobat Reader from Acrobat/Edit>Preferences>Document>'Always use the filename as document title' Click OK and restart the application.

Let us know if that works for you.

Thanks,

Anand Sri.