You found a new screenshot, another identical case happened, or you remembered an important detail: all of that should go to the ticket you already have open, not to a new one. Keeping the context in a single conversation is what speeds up a resolution the most.
Steps
Reply in the same conversation
Reply to the ticket's latest email or continue the same chat thread. Your reply is automatically added to the case history and notifies the assigned agent.
Mention the ticket number if you switch channels
If you opened the case by chat and are now writing by email (or vice versa), include the ticket number in your message so Support can link it to the existing case.
Add only what's new
Don't repeat what you already reported: point out which information is new — additional IDs, screenshots, something that changed since your last message — and how it relates to the case.
After you add the information, the ticket status is updated and the case resumes its course. You can check its progress at any time by looking up the status of your request.