A shipper of dangerous goods is obligated to attend an IATA accredited DG training course and acquire qualification which is valid for 2 years in accordance with UN ICAO requirements which is reflected in the local government regulations. If there is(are) no qualified person(s) in employment, the shipper may outsource part of or the entire shipping job function to a logistic company (cargo agent, freight forwarder or a consolidator). However, if anything goes wrong or if an accident happens, not only the logistic company will be liable but the shipper will also be held liable for any damages.
Therefore, even if you may outsource part of or all of the job functions, the shipper will still be held responsible and accountable. It would therefore be better for the shipper to acquire qualification and be able to know the regulations and understand what the logistic company is doing. This qualification is valid internationally and is obligated by UN ICAO (International Civil Aviation Organization). It is incorporated in the Japanese Aviation Codes which obligates qualified personnel with a valid 2 year qualification to be present at each working location. The qualification can be extended for 2 years by attending a recurrent course. By accessing our website, you will be able to acquire information on our training courses. As to what point will the shipper transfer the chain of jobs to a logistic company is a matter of discussion with the logistic company. The cut-off point can be at any stage. Such will depend on the contract between the shipper and the logistic company. No matter where the transfer point is, the final responsibility of the shipment lies with the shipper.
As for opening an inbound package containing lithium batteries, and sending them out using the same packaging material, you will need a qualified person to pack, mark, label and prepare transport documentation. It would be better if you address your question to specific steps thence the response will be more to the point. Only general answers can be given to a general question.