Any licensed facility or agency as defined, upon petition and showing of good cause therefor, to the satisfaction of the board may reduce, curtail or eliminate any service or facility which might otherwise be required for licensure by the board. A showing that the service or facility is unnecessary by reason of an arrangement with another facility or agency as defined, pursuant to section 39-1303b, Idaho Code, shall be conclusively deemed to be a showing of good cause under this section, and any licensed facility or agency as defined which, prior to January 1, 1976, had already reduced, curtailed or eliminated any service or facility by reason of the same being provided by another licensed facility or agency as defined, in the same community shall be deemed to have complied with this section.