To resolve a ticket, run resolve-ticket ticket-number. You can then enter text, typing Control-D to end text entry. The text of this resolution will be mailed to the person who entered the ticket into the system. (If you changed the ticket requestor via the requestor-ticket command, that person will be mailed instead of the ticket creator.) To suppress mailing the response text, run resolve-ticket --nomail ticket-number instead.
There are some additional commands, to mark tickets as being changed when another ticket is altered. pending-on will set a ticket as pending until the given ticket number is resolved, at which point it will revert to assigned (or new) status; resolve-when will resolve the ticket when the master ticket is resolved. Check Reference I, BATTS Manual Pages for more information.