Replication :: Error During Add New Master In Not Acquiescing Mode

I have a multimaster replication between 2 sites (BASE1 and BASE3). BASE1 is the master definition site. I want to add a new master site without acquiescing the master group (named GM_ADMINISTRATEUR).

First, I have used the script provided by Oracle :

DBMS_REPCAT.SPECIFY_NEW_MASTER (
gname => 'GM_ADMINISTRATEUR',
master_list => 'BASE2.WORLD' );
and
DBMS_REPCAT.ADD_NEW_MASTERS( ....);

The first time, I had Errors, so I use the command

DBMS_REPCAT.UNDO_ADD_NEW_MASTERS_REQUEST

and I drop the master site BASE2 (connected as repadmin to BASE2 site).

The master site BASE2 is not present at BASE1 master definition site, The master repgroup is not present at BASE2 BUT, the master site BASE2 is always present at BASE3 master site. I think that the command UNDO_ADD_NEW_MASTERS_REQUEST undo the changes on BASE1 (the master definition site) but don't undo the changes on the site BASE3.

And now, when I want redo the add_new_masters, the command

DBMS_REPCAT.ADD_NEW_MASTER
return a error on the command ADD_NEW_MASTER in the DBA_REPCATALOG for the following reason:
ORA-00001: violation de contrainte unique (SYSTEM.REPCAT$_REPSCHEMA_PRIMARY)
ORA-06512: � "SYS.DBMS_REPCAT_UTL", ligne 4484
ORA-06512: � "SYS.DBMS_REPCAT_RPC", ligne 1758

And I can't continue because the new master site BASE2 does not appear at BASE1 master definition site. I think I have to drop the master site BASE2 at the master site BASE3, but I dont know how to do this.

**** Following information at BASE1 (master definition site : *****
prompt Replication schemas/ sites
Replication schemas/ sites
select
sname,
masterdef,

[code].....