How to reduce FRA usage alert from 85% to 60% or less?

If you are using Fast Recovery Area (FRA) for the archive log destination and the destination is set to USE_DB_RECOVERY_FILE_DEST,

Archive log auto deletion is configured using CONFIGURE ARCHIVELOG DELETION POLICY TO APPLIED ON ALL STANDBY BACKED UP 1 TIMES TO DISK;

In case of FRA space crunch, oracle deletes files from FRA and this triggered at 85% , in our setup we want file deletion should be triggered at 60% or less.