DROP STATISTICS — remove extended statistics
DROP STATISTICS [ IF EXISTS ] name [, ...]   DROP STATISTICS removes statistics object(s) from the
   database.  Only the statistics object's owner, the schema owner, or a
   superuser can drop a statistics object.
  
IF EXISTSDo not throw an error if the statistics object does not exist. A notice is issued in this case.
nameThe name (optionally schema-qualified) of the statistics object to drop.
To destroy two statistics objects in different schemas, without failing if they don't exist:
DROP STATISTICS IF EXISTS
    accounting.users_uid_creation,
    public.grants_user_role;   There is no DROP STATISTICS command in the SQL standard.