Before applying any interim CPU patch that is applied through OPatch, it is strongly recommended to perform a prerequisite check in the
ORACLE_HOME file that you are going to patch. Patches that are specific to security may be some of the patches that are already applied. Such a patch/patches needs to rollback and again has to apply a merge patch after applying security patches. These merge patches can be requested from Oracle support if they aren't available. Note that no down time is required to perform this check.
You can perform the prerequisite check as follows:
opatch prereq CheckConflictAgainstOHWithDetail -phBaseDir /home/oracle/patches/9711859 Oracle Interim Patch Installer version 18.104.22.168.0