Parties having their residence or principal place of business in a contracting state are not obliged to be represented by a professional representative in proceedings before the EPO. They may, irrespective of whether they are legal or natural persons, act through an employee, who need not be a professional representative but who must be authorised (see A-VIII, 1.6, and A-VIII, 1.7). [Art. 133(3); Art. 134(1); Rule 152; ]