Subject to the next sentence, no person may be compelled to be represented by a professional representative in proceedings before the EPO; this holds for all parties to such proceedings, e.g. applicants, proprietors, opponents. A party (natural or legal person) who has neither his residence nor principal place of business in a contracting state must be represented by a professional representative; the party must act through this professional representative in all proceedings, other than in filing the application (which includes all acts leading to the assignment of a date of filing) or initiating the European phase within the applicable time limit (see E‑IX, 2.3.1). To "be represented" is to be interpreted as meaning due representation, including not only notice of the appointment of a professional representative but also, where applicable, the filing of authorisations of the appointed representative (see A‑VIII, 1.5). Should an opponent who is party to the proceedings and does not have either a residence or his principal place of business within the territory of one of the contracting states fail to meet the requirement set out under Art. 133(2) in the course of the opposition procedure (e.g. the representative withdraws from the opposition case or the appointed representative is deleted from the list of professional representatives), he is requested to appoint a new representative. Irrespective of whether he does so, he should nevertheless be informed of the date and location of any oral proceedings. However, it has to be drawn to his attention that if he appears only by himself he is not entitled to act before the Division.