4. The Commission, after consulting the Board shall, upon a joint request from at least three participants, authorise the establishment of an interoperability regulatory sandbox. Where appropriate the request shall specify information such as the purpose of the processing of personal data, the actors involved and their roles, the categories of personal data concerned and their sources, and the envisaged retention period. The consultation shall not replace the prior consultation referred to in Article 36 of Regulation (EU) 2016/679 and Article 40 of Regulation (EU) 2018/1725. Where the interoperability regulatory sandbox is established for interoperability solutions supporting the cross-border interoperability of trans-European digital public services by one or more Union entities, including with the participation of public sector bodies, no authorisation shall be required.