Modify indexes on a delta-syncrepl consumer

Hello,

I am using two OpenLDAP 2.4.31 servers with delta-syncrepl as replication method. So far everything works perfectly but I was wondering how I can modify cn=config settings on the consumer. For instance I would like to add new indexes (olcDbIndex) on the consumer to my replicated HDB database but this fails as you can see here:

ldap_modify: Server is unwilling to perform (53)     additional info: shadow context; no update referral

I understand that it does not want me to modify any settings on my consumer but I was thinking this should be possible no? If not this means if I want to change a setting on the consumer I need to delete my whole database on the consumer configure it and add replication again.

Any one has an idea what am I doing wrong here?

Cheers, M.L.