Hey Lekhu,
There is a good tutorial - how-to-deal-with-s4-connector-rejects.
I hope you have reviewed it already because there is the example how to use embedded tools for comparing entries in OpenLDAP and Samba4.
Therefore, according to your post, I guess you need to use the following command for getting result:
# User
univention-ldapsearch -b "uid=john smith, ou=administrators, ou=users, ou=ABC, dc=intranet, dc=local"
univention-s4search -b "cn=john smith, ou=administrators, ou=users, ou=ABC, dc=intranet, dc=local"
After actions should be done according to the official tutorial.
Hope this helps you.