If a patent agency is not entrusted, the procedures for changing the description items shall be handled by the applicant (or patentee) or his representative; If a patent agency has been entrusted, it shall be handled by the patent agency. Changes caused by the transfer of rights may also be handled by the new obligee or the patent agency entrusted by him.
The above quotation is from Patent Examination Guide 20 10. Is that clear?
The change of the first patentee and the change proposed by the original patentee must be handled by the original agency; If it is proposed by the new patentee, there is no need to find the original agency to handle it.