2.1 Admissibility 

The correction of linguistic errors, errors of transcription and other mistakes in any document filed with the EPO may in principle be requested as long as proceedings are pending before the EPO (J 42/92). However, during examination proceedings, such requests for correction can be considered only if the decision-making process has not yet been concluded, in other words at the latest on the day before the date until the day on which the decision to grant is handed over to the EPO's internal postal service for transmittal to the applicant (see G 12/91; date "to EPO postal service" printed at the bottom of Form 2006A). See also H‑II, 2.6, last paragraph.

Moreover, other time limitations apply to requests under Rule 139:

(i)The request has to be made without undue delay after the error is discovered (G 1/12, J 16/08).

(i)(ii) In the case of correction of bibliographic data (e.g. priority, designation) or of procedural declarations (e.g. withdrawal), time limitations may derive from the protection of the interests of the public. For instance, in the absence of any special circumstances, a request for correction of a priority claim by the addition of a first priority needs to be made sufficiently early for a warning to be included in the publication of the application (J 6/91). Otherwise, correction is possible only where it is apparent on the face of the published application that a mistake has been made (see also A‑V, 3). An erroneous withdrawal of an application may only be corrected if, at the time when the request for correction is made, the public has not yet been officially notified of the withdrawal (J 25/03).

(ii)(iii) Limitations on requesting the correction of an error in a document filed with the EPO also exist where a decision has already been taken or a procedural phase terminated on the basis of the document containing the error. A request under Rule 139 cannot reinstate an applicant into an earlier procedural phase or reverse the effects of a decision already taken (J 3/01, see also H‑VI, 3.1). Such a request is therefore inadmissible in these cases.