Often, users do post into a thread where their post doesn't fit or is otherwise undesirable. In this case, we have to split those post off into a new topic. phpBB offers 2 options. A moderator can either take selected posts out of a topic or split all posts following a certain post off.
To split posts off, proceed as follows.
1.) While viewing the thread (not the subforum!), select Moderator Control Panel
2.) Enter a name for the new topic and select the appropriate subforum for the split off topic
3.) Select the post(s) to split
a) If you want to split off all posts following one, select only the first post which should be split off, then choose "Split topic from selected post onwards".
b) If you only want to take out selected posts, select all post you want to take out and the choose "Split selected posts"
After selection click "Submit"
4.) Add a post to the newly created topic, indicating that you split the posts off, from where you split them off and why (if the reason is not self evident).