How to decrease no.of channels in RMAN cnfiguration parameters

Hi,

we need to decrease RMAN channels from 8 to 6

CONFIGURE RETENTION POLICY TO REDUNDANCY 1;

CONFIGURE BACKUP OPTIMIZATION OFF;

CONFIGURE DEFAULT DEVICE TYPE TO DISK;

CONFIGURE CONTROLFILE AUTOBACKUP OFF;

CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F';

configuration for DISK channel 7 is ignored

configuration for DISK channel 8 is ignored

CONFIGURE DEVICE TYPE DISK BACKUP TYPE TO COMPRESSED BACKUPSET PARALLELISM 6;

CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1;

CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1;

CONFIGURE CHANNEL 1 DEVICE TYPE DISK FORMAT   '/backups/ora_db_%d_%T_%s.rman';

CONFIGURE CHANNEL 2 DEVICE TYPE DISK FORMAT   '/backups/ora_db_%d_%T_%s.rman';