ORA-29972: user does not have privilege to change/ create registration

===============
Issue:
===============

login an dba privileged user and from existing user:

SQL> DROP USER MY_USER CASCADE;

DROP USER MY_USER CASCADE

*

ERROR at line 1:

ORA-29972: user does not have privilege to change/ create registration

===============
Details
===============

In Oracle 12 there is a new feature Change Notification. 
This is a system privilege.
For some reason, you need to revoke this privilege before you can drop the user.

===============
Solution:
===============
SQL> REVOKE CHANGE NOTIFICATION FROM MY_USER;

Revoke succeeded.

SQL> DROP USER MY_USER CASCADE;

User dropped.