When an applicant is represented by a professional representative, a request for restitutio in integrum cannot be acceded to unless the representative himself can show that he has taken the due care required of an applicant or proprietor by Art. 122(1) EPC (J 5/80, OJ 1981, 343). In other words, what Art. 122 EPC requires from an applicant also applies to an applicant's representative (T 1149/11).
The extensive case law on a professional representative's duty of care in dealing with assistants is dealt with below in point 4.5.4.