Term Management Tools

Set Parent option. In this case, the term "New EN" will be set as a child of "Parent One EN"

Merge option. Here, the two selected terms will be merged into a new term named "Merged." In addition, because both source terms share the same parent term ("Parent One EN"), the new term will also have "Parent One EN" as its parent term.

Change Taxonomy option. Here, the "Parent One EN" category will be sent to the custom taxonomy "Hierarchical" (which I added for the sake of testing). A few other things to note here. First, the two child terms will also be moved and, because the target taxonomy is also hierarchical the parent-child relationships will be preserved. Second, if there are any WPML translations of these terms, they will also be moved and the translations maintained.