1)Stop database using srvctl (srvctl stop database -d database name)
2) Remove the database entry from crs -(srvctl remove instance -d database -i instance name)
3) Start the database on first instance
4)alter system set custer_database=false scope=spfile;
5)alter system set cluster_database_instance=1 scope=spfile;
6)disable unwanted threads,drop unwanted redolog groups and drop the unwanted tablespace.
