To rename database national character set

When creating a new database, the NCHAR was not set properly for 11GR2.
 We followed the below steps in order to change NCHAR set.  
Steps to be followed, 
 Step 1: shutdown immediate;  
Step 2: startup mount;  
Step 3: alter system enable restricted session;
Step 4: alter system set job_queue_processes=0;
Step 5: alter system set aq_tm_processes=0;  
Step 6: alter database open;  
Step 7: alter database national character set UTF8;  
Step 8: shutdown immediate;  
Step 9: Startup  
Step 10: Check NCHAR values