"The repair facility shall appoint a person ('responsible person') with the required competency (see Annex B), within the management organization, to accept responsibility and authority for ensuring that the overhauled/repaired equipment complies with the certification status agreed with the user. The person so appointed shall have a working knowledge of the appropriate explosion protection standards and an understanding of this standard."
This is what the 60079-19 standard says on responsible persons at the repair facility, a member of staff who is not in a management position can become the responsible person but must have the relevant training and knowledge of Ex repairs & procedures and be willing to take the responsibility of checking, inspecting & signing off work carried out by others, they also need to be named as “The Responsible Person” by the repair facility.