A board may choose to remit a case to the department of first instance as a result of observations filed under Art. 115 EPC. See, for example, T 249/84 and T 176/91 of 10 December 1992 date: 1992-12-10.
In T 929/94, a preliminary examination by the board of the third-party observations and the supporting material showed that an entirely new case based on new facts and evidence had been presented against the patentability of the claimed invention in these observations. In order to preserve the applicant's right to review through appeal of any adverse decision of the department of first instance, the board remitted the case for examination of and decision upon such new material, as requested by the applicant.
In T 41/00, a document submitted during the appeal proceedings by a third party under Art. 115 EPC 1973 appeared to come closer to the claimed subject-matter than any of the prior-art citations considered during the examination proceedings. However, since it remained open to question whether the document had been available to the public at the patent's priority date, the case was remitted to the department of first instance.
In T 848/06 the board intended to remit the case to the department of first instance. The board concluded that it would not be appropriate for the board to take into account the third party observations so as not to prejudice their consideration by the said department.
In T 30/01 the case was remitted to the department of first instance for further prosecution. The board stated that the opposition division would also have to consider whether to admit or disregard the observations presented during the appeal proceedings by the third party and partially incorporated by reference in the respondent's own case.