29 C.F.R. § 102.93
If, either before or after service of the Notice of Hearing, the parties submit to the Regional Director satisfactory evidence that they have adjusted the dispute, the Regional Director will dismiss the charge and will withdraw the Notice of Hearing if Notice has issued. If, either before or after issuance of the Notice of Hearing, the parties submit to the Regional Director satisfactory evidence that they have agreed-upon methods for the voluntary adjustment of the dispute, the Regional Director will defer action upon the charge and will withdraw the Notice of Hearing if Notice has issued. If it appears to the Regional Director that the dispute has not been adjusted in accordance with such agreed-upon methods and that an unfair labor practice within the meaning of Section 8(b)(4)(D) of the Act is occurring or has occurred, the Regional Director may issue a complaint under § 102.15 , and the procedure prescribed in §§ 102.9 through 102.51 will, insofar as applicable, govern; and §§ 102.90 through 102.92 are inapplicable, except that if an agreed-upon method for voluntary adjustment results in a determination that employees represented by a Charged Union are entitled to perform the work in dispute, the Regional Director will dismiss the charge as to that union irrespective of whether the employer has complied with that determination.
29 C.F.R. §102.93