"4.2.6. Splitting posts off a topic
Moderators also have the ability to split posts from a topic. This can be useful if certain discussions have spawned a new idea worthy of its own thread, thus needing to be split from the original topic. Splitting posts involves moving individual posts from an existing topic to a new topic. You may do this by using the QUICK MOD TOOLS area beneath the topic you want to split or from the Moderator Control Panel within the topic.
While splitting, you may choose a title for the new topic, a different forum for the new topic, and also a different icon. You may also override the default board settings for the amount of posts to be displayed per page. The SPLITTING FROM THE SELECTED POST option will split all posts from the checked post, to the last post. The SPLITTING SELECTED POSTS option will only split the current selected posts.
4.2.7. Merge topics
In phpBB3, it is now possible to merge topics together, in addition to splitting topics. This can be useful if, for example, two separate topics are related and involve the same discussion. The merging topics feature allows existing topics to be merged into one another.
To merge topics together, start by locating selection menu beneath the topic in question, which brings you to the Moderator Control Panel. From here, you need to enter the topic ID of the topic you want to move the posts to. You can click SELECT TOPIC to see a list of the topics available and specify which. Checking the MARK ALL section will select all the posts in the current topic and allow moving to the existing topic. The posts merged into the new topic will retain their existing timestamp (e.g. they will not appear at the end of the topic they are being merged to, but will be sorted based on their timestamp).
4.2.8. Merge posts into another topic
Rather than just merging topics together, you can also merge specific posts into any other topic.
To merge specific posts into another topic, start by locating the selection menu beneath the topic, and get to the Moderator Control Panel. From here, you need to enter the topic ID of the topic you want to move the posts to. You can click SELECT TOPIC to see a list of the topics available and specify which. Select the posts which you wish to merge from the current topic, into the existing topic. The posts merged into the new topic will retain their existing timestamp (e.g. they will not appear at the end of the topic they are being merged to, but will be sorted based on their timestamp)."
Fuente:
https://www.phpbb.com/support/documenta ... dtools.php
Me parece que las evidencias son suficientes, ¿objeciones?