When a customer replies to an old, closed ticket, Zoho Desk automatically reopens it, and this raises a natural question about how that affects the ticket's resolution time and SLA figures.
A response to an old ticket reopens it, and the ticket sits in an Open status until it's manually closed again. The resolution time calculation only counts the genuine open time, meaning if the ticket was only reopened for a few minutes before being closed again, only those few minutes are added to the SLA and reporting figures, rather than counting time that elapsed while the ticket was originally closed and dormant.
This distinction matters because it means a ticket that's been closed for months and then briefly reopened by a late reply doesn't get penalised in your SLA metrics for the entire dormant period. Only the actual active time the ticket spent open counts.
If the new reply is actually about something unrelated to the original issue, rather than a genuine follow-up, the specific thread can be split off into a brand new ticket instead of reopening the old one, which keeps your reporting and resolution time cleanly separated between the two distinct issues.