An applicant for or proprietor of a European patent who, despite taking all due care required by the circumstances, was unable to observe a time limit vis-à-vis the European Patent Office not specifically excluded by Art. 122(4) and Rule 136(3) may apply to have his rights re-established. According to Art. 122(4) and Rule 136(3), re-establishment of rights is ruled out in respect of all periods for which further processing is available and in respect of the period for requesting re-establishment of rights. Re-establishment applies to the time limit under Rule 135(1) for requesting further processing and also to the time limits which are excluded from further processing according to Art. 121(4) and Rule 135(2). This means that, where further processing applies to a time limit, re-establishment cannot be requested for failure to observe that time limit. However, if further processing is available, but the applicant fails to request it in time, re-establishment of rights according to Art. 122 is available for the time limit for requesting further processing. Moreover, re-establishment of rights is possible where an applicant fails to file his application within the priority period of Art. 87(1). The conditions governing this application are fully set out in Art. 122(1) to Art. 122(6) and Rule 136(1) to Rule 136(4). The provisions of Art. 122 and Rule 136 might be invoked if e.g. the applicant's working documents have been destroyed by fire and he has been obliged to prepare fresh ones; or if a specialist agency sent him the wrong set of drawings relating to a priority document, and the error was not immediately apparent. In all instances it is necessary for the applicant or proprietor or representative, as the case may be, to supply evidence that he had exercised all due care required by the circumstances and that the delay was caused by unforeseeable factors. Errors of law, however, do not constitute grounds for re-establishment (see e.g. D 6/82, J 31/89 and J 2/02).