Move single Clientbackups vom Server A to Server B

Server A = FreeBSD and ZFS Storage
Server B = Debian and Btrfs Storage

What is the best procedure to move a single Client-Backup to the other Server…
not the the whole /urbackup storage only 1 single Client-Backup (about 2 TB data)

(i checked FAQ,AdminPDF and search in forum but found no information/solution)

thanks for any hint