Appointment of an agent, common agent or common representative for the international phase requires a declaration to that effect. This can be made either in the PCT request (Box No. IV PCT request form) itself or in a separate notice ("power of attorney"). For this purpose the "PCT/Model of power of attorney" may be used, which is available on the WIPO website.[ 20 ] If the agent, common agent or common representative is at the same time to be appointed for the procedure in the European phase, please refer to the information in points 114 ff.
For the appointment of the agent, the common agent or the common representative to be effective, the PCT request or the power of attorney must be duly signed by (all) the applicant(s) for whom the agent, the common agent or the common representative is intended to act (see points 110 ff and points 165 ff).
Please note that a power of attorney may not be filed by fax or using the EPO web-form filing service (see point 67).
Source: http://www.epo.org/applying/international/guide-for-applicants/html/e/ga_b_21.html
Date retrieved: 30 December 2018