In addition to create new and create new with dependencies copy options, you can do the following:
Replace the target planning area with the source planning area
Merge the source planning area with the target planning area
Replace the target planning area with the source planning area including dependencies (IDs of the target planning area and master data types are kept)

Merging two planning areas causes the deltas from the source planning area to be merged with the target planning area.
Copy Merge Results
The figure, Merge Results, shows the copy merge results.
