to Thomasps. Thanks !
But DB_FILE_NAME_CONVERT convert name of db_files but not the RMAN's backup files. I backuped to "backup database format='/oracle/%d_DB_%u.rman';"
Then I copy %d_DB_%u.rman to host_B to the another path !!!! /ORACLE2 and then I want to restore use RMAN but it can not find file "%d_DB_%u.rman" because it is /ORACLE2/%d_DB_%u.rman