351.1 Mutual Assistance Art. 80 Preliminary examination The request shall be subject to preliminary examination by the cantonal or federal authority responsible for its execution. 1 If the request cannot be granted, the executing authority shall return it to the requesting authority by the same channel through which it was received. 2 Art. 80a Consideration and execution The executing authority shall issue a summary ruling on whether to consider the case and shall order the mutual assistance measures permitted. 1 2 It shall execute the mutual assistance measures in accordance with its own procedural law. Art. 80b Participation in the proceedings and access to the files The persons entitled may participate in the proceedings and have access to the files provided this is necessary to safeguard their interests. 1 2 The rights provided for in paragraph 1 may be limited only: a. in the interest of the foreign proceedings; b. for the protection of an important legal interest if the requesting State so requests; c. because of the nature or urgency of the measures to be taken; d. for the protection of important private interests; e. in the interest of Swiss proceedings. Access to the files or participation in the proceedings may only be denied in the case of files or procedural measures for reasons of confidentiality. 3 Art. 80c Simplified execution The persons entitled, and in particular the holders of documents, information or assets may consent to handing them over without formality at any time prior to the conclusion of the proceedings. Consent is irrevocable. 1 2 If all the persons entitled give their consent, the competent authority shall make a written record thereof and conclude the proceedings. If only some of the documents, information or assets required are handed over, the ordinary proceedings shall be followed for the remaining part. 3 Art. 80d Conclusion of the mutual assistance proceedings When the executing authority determines that the request is completely or partially executed, it shall issue a ruling giving reasons on whether mutual assistance is granted and to what extent. 30