As a product owner we do often run into cases where a follow-up backlog item or defect needs to be created. This can be done manually by creating the new item and linking dependencies afterwards (look-up the id of the original item, look-up the portfolio item etc...) but it would be much more convenient to have a dedicated command similar to the copy command.
Another possibility would be to use the copy command to get some details like portfolio copied directly. But this might copy too much information (tests that have been run already) and is still missing the dependency to the original item.