As documented in the TPI guide for RESTO:
RESTO Record is OPTIONAL
In a VOLSER restore job exception file, use the RESTO record to specify a domain to which to restore data (a target domain).
You must specify a RESTO record for every source domain whose data the job will restore to a target other than the source.
This record is valid only in VOLSER jobs. VM:Backup ignores this record in CATSEARCH and VOLSEARCH jobs.
Note: This record is available only through TPI. Using this record will prevent you from managing the exception file through the VM:Backup screens.
A file can include one RESTO record for each EXCEPT record in the file. If the file does not include a RESTO record, the job restores the data to the same location from which it was backed up (the source).
RESTO {"Options"}
Options:
BFSDIRECTORY filespace fulldirpathname
DIRECTORY fqdirname
DISK userid vaddr
FILESPACE filepoolid:userid
RDR userid
https://docops.ca.com/ca-vm-backup-for-zvm/3-6/en/template-programming-interface/restore-job-exception-files/resto-record