multitenant update awr retention in mutitenant 19c

2 node RAC 19c database for EBS 12.2.3 on Linux

I am having trouble knowing what to source and log in a multitenant architecture to do mainteance on the db.

I would like to update the retention period on awr reports.

I can do this in a non multitenant database.

1. find the dbid ( select dbid from v$database)
2. find all the dbid's in the db : select dbid from dba_hist_wr_control;
3. delete all but the dbid in v$database
4. select 'exec dbms_swrf_internal.unregister_database('||dbid||');' from dba_hist_wr_control;
5. update the retention period for awr: