DROP CONVERSION removes a previously defined conversion. To be able to drop a conversion, you must own the conversion.
Do not throw an error if the conversion does not exist. A notice is issued in this case.
The name of the conversion. The conversion name can be schema-qualified.
These key words do not have any effect, since there are no dependencies on conversions.
There is no DROP CONVERSION statement in the SQL standard, but a DROP TRANSLATION statement that goes along with the CREATE TRANSLATION statement that is similar to the CREATE CONVERSION statement in PostgreSQL.