Rule 137¹⁴³,¹⁴⁴
Amendment of the European patent application

(1) Before receiving the European search report, the applicant may not amend the description, claims or drawings of a European patent application unless otherwise provided. 

(2) Together with any comments, corrections or amendments made in response to communications by the European Patent Office under Rule 70a, paragraph 1 or Rule 70a, paragraph 2, or Rule 161, paragraph 1, the applicant may amend the description, claims and drawings of his own volition.

(3) No further amendment may be made without the consent of the Examining Division. 

(4) When filing any amendments referred to in paragraphs 1 to 3, the applicant shall identify them and indicate the basis for them in the application as filed. If the Examining Division notes a failure to meet either requirement, it may request the correction of this deficiency within a period of one month.

(5) Amended claims may not relate to unsearched subject-matter which does not combine with the originally claimed invention or group of inventions to form a single general inventive concept. Nor may they relate to subject-matter not searched in accordance with Rule 62a or Rule 63.