Amendments and/or arguments filed under Article 34 PCT should preferably be filed together with the demand. Furthermore, as the EPO will start the preliminary examination as soon as it is in possession of all the elements listed in Rule 69.1(a) PCT, if the applicant wants to make amendments but is not ready to file them at the same time as the demand, he should always indicate so by checking the corresponding box(es) in Box No. IV, item 1 of the PCT demand Form (PCT/IPEA/401). Otherwise, the EPO is allowed to start the international examination on the basis of the application as filed. Subsequently filed amendments and/or arguments will only be taken into account by the EPO as IPEA if they are received before the point at which preparation of a written opinion or the IPER has actually started. Moreover, if a second written opinion is established (see point 4.2.017), subsequently filed amendments and/or arguments will be taken into account together with the reply to the second written opinion. Amendments and/or arguments not taken into account by the EPO as IPEA may be (re-)filed with the elected Offices upon entry into the national phase.

If the EPO acted as ISA, the EPO as IPEA will consider the WO-ISA as a first written opinion for the purposes of international preliminary examination and, as a rule, commence the international preliminary examination as soon as it is in possession of all the elements listed in Rule 69.1(a) PCT, unless the applicant expressly requests to postpone the start of the international preliminary examination until expiry of the time limit for filing the demand (see points 4.2.021 ff). Therefore, it is important that amendments and/or arguments under Article 34 PCT are filed in due time.

Applicants must make sure that none of the amendments go beyond the disclosure in the international application as originally filed. Note that if an amendment contains a negative limitation, e.g. a "disclaimer", the EPO as IPEA in accordance with the discretion provided for in the ISPE Guidelines applies the same approach as in respect of a Euro-direct application (see the Annex to this Guide). Further, applicants must indicate in an accompanying letter 

If the basis for any amendment is not indicated as required, the EPO will establish the written opinion and/or IPER as if no amendments had been filed and without first issuing a reminder. 

If amendments to the claims are filed a complete set of the claims in replacement of all claims originally filed must be submitted.