According to this blog post from Android Developers blog, no, you cannot change package name unless you're okay with publishing it as a new app in Play Store:
Once you publish your application under its manifest package name,
this is the unique identity of the application forever more. Switching
to a different name results in an entirely new application, one that
can’t be installed as an update to the existing application.
Android manual confirms it as well here:
Caution: Once you publish your application, you cannot change the
package name. The package name defines your application's identity, so
if you change it, then it is considered to be a different application
and users of the previous version cannot update to the new version.
If you're okay with publishing new version of your app as a completely new entity, you can do it of course - just remove old app from Play Store (if you want) and publish new one, with different package name.