If there are conflicts between the contents of a topic stream and its parent, you must resolve them before you can merge the pull request.
A banner at the top of a pull request indicates if there are conflicts and it cannot be merged into the target stream.
Conflicts are resolved and merged into a topic stream via a work area.
In example below there are conflicts between the content of topic stream Feature_1 and Mainline:
The parent stream, Mainline, is merged into the work area associated with the topic stream, Feature_1.
The conflicts are resolved during the merge operation.
The merge results are delivered to the topic stream from its work area.
Pull request PR1 is merged, which automatically applies all the topic stream changes to the parent stream.