Hi @cloudera-a ,
Since the CM server ships with embedded PostgreSQL DB, our docs point to migrating from PSQL to MySQL or even Oracle, but not the other way around.
For instance, here's our doc to migrate from a PostgreSQL Database Server to a MySQL/Oracle Database Server [0].
You could make use of a 3rd party tool to achieve what you're trying to do, but this won't be encouraged by Cloudera, as this could easily lead to an unstable cluster.
[0] = Migrate from the Cloudera Manager External PostgreSQL Database Server to a MySQL/Oracle Database Ser...