Merge Topics Option?

I thought we used to have a merge option, but I'm not seeing it anymore.
I started topic A in the past but a member posted something under Topic B which belongs in Topic A.
How do I move the Topic B post to the existing Topic A?

Hi,

Did you have button pictures associated with your moderator tools? The button for merging might have been lost after the recent server upgrades. Check in your admin panel to see if your button is still there.