With a manual edit of the dse.ldif configuration file after it is saved/duplicated.
Look and "carefully" select entries with definitions for
objectClass: nsds5replicationagreement
similar to for example
dn: cn=meTods2.example.test,cn=replica,cn=dc\3Dexample\2Cdc\3Dtest,cn=mapping tree,cn=config
and remove the corresponding paragraph.
Also review the entry similar to this example:
dn: cn=replica,cn=dc\3Dexample\2Cdc\3Dtest,cn=mapping tree,cn=config
with a definition for
objectClass: nsds5replica
remove the nsState
or eventually remove the whole paragraph if not longer needed
Also review the paragraph with definition for
nsslapd-backend: xx
similar to this example
dn: cn=dc\3Dexample\2Cdc\3Dtest,cn=mapping tree,cn=config
nsslapd-backend: userRoot
nsslapd-state: backend
and review the nsslapd-referral: attribute value
If there are more than 2 servers, the corresponding nsds50ruv would need to be cleaned up on the other systems.
it may be "easier" to run the DS console, and faster to create a new replica from "scratch" (that seem urgent if this now a single point of failure scenario)
and it may be interesting to collect a core file and stack trace if the version is current on the crashed system.
Thanks,
Marc S.