When filing your patent application by reference to a previously filed application, you should indicate in the request for grant form (section 26.1) the filing date, application number and the state in which that application was filed. The reference must indicate that it replaces the description and/or any drawings. You will then have to file a certified copy of the previously filed application within two months of filing the application. If the reference application is not in English, French or German, you must file a translation thereof within the same time limit. If you do not file the certified copy within the said time limit or within a time limit set in a subsequent invitation, the application will not be dealt with as a European patent application. If you do not file a translation of the previously filed application within the said time limit or within a time limit set in an invitation, the application will be deemed to be withdrawn.