How to convert unused physical standby to normal database?

We have two physical standby databases. One of them are shutdown for long time. I want to reopen it as a normal database because it has data already.

And I want to change the database name and db_id as well.

It looks like the nid (DBNEWID) does not work on standby database. I have to convert it normal database first.

I already remove this standby database from DGMGRL.

I already changed all parameters that relates to data guard on this database and restart mount.

startup mount

alter system reset log_archive_config scope=spfile;

alter system reset fal_server scope=spfile;