A topic with more than two posts can be split into separate topics.
Go into the topic you want to split.
Click on the Action bar, and select Split from the drop-down menu. The Split Topic form opens.
Enter the name for the new topic in the New Topic field.
Select posts by ticking their respective checkboxes.
The new topic will be displayed in the topics list with the new name. The last selected post will become the main entry of the new topic.