If you do not see the bump/edit/relist option the thread is not currently eligible to be bumped. Once you are eligible to bump the thread, the option should appear.
The thread was created prior. I was shown the message that i wanted to relist again, I would need a premium account. Now i don't get the option at all....
Regular users can bump a thread once every 30 days. Premium users can bump/relist once every 7 days. If you've already bumped a thread within the last 7 days, the option won't be available. (I'm not a moderator/DP-admin, so take what I say here with a grain of salt).
See this post: https://forums.digitalpoint.com/threads/how-to-bump-up-your-old-dp-threads.2761287/#post-19214319