If the search division or the ISA raises an objection of lack of unity, a further search fee is payable under R. 64(1) EPC (R. 46(1) EPC 1973) or Art. 17(3)(a) PCT, respectively, for each additional invention to be covered by the second report (for Euro-PCT applications in the European phase, see in this chapter II.B.6.2.). See also OJ 2017, A20 for the provisional opinion now issued together with the partial search report. If the fee is paid in due time applicants may select the single invention or group of inventions which they wish to retain in the (main) application.
This choice cannot be altered once examination of that invention has commenced (T 158/12, with reference to G 2/92). If an applicant responds unclearly or in a misleading way to an invitation from the examining division to specify which searched invention it wishes to prosecute further, then the division has to clarify this matter, e.g. via a further communication (T 736/14).
Source: http://www.epo.org/law-practice/legal-texts/html/caselaw/2019/e/clr_ii_b_6.htm
Date retrieved: 17 May 2021