This chapter concerns the allowability of amendments under Art. 123(2) and (3) EPC, as well as corrections of errors in the parts of a patent application or of a patent relating to the disclosure (the description, claims and drawings) under R. 139 EPC. Other aspects related to amendments are dealt with elsewhere; see for example chapters II.D.3.1.2 in the context of Art. 87(1) EPC; II.F. "Divisional applications", in particular II.F.2.2. "Amendments to divisional applications"; III.I.3.1. "Party's responsibility to define subject-matter by filing appropriate requests"; III.L. "Correction of errors in decisions"; IV.B.1.1., IV.B.2.6., IV.B.3.3., IV.B.3.4., IV.B.3.6., IV.B.3.7., IV.B.5. for the admissibility of amendments during the "Examination procedure"; IV.C.5. "Amendments in opposition proceedings"; V.A.4. "New submissions on appeal".