The search results indicate that KSIQ changed its call letters to KYDO. The station was assigned the KSIQ call letters on March 25 of a certain year and began broadcasting on September 10 of the same year with a Top 40 format. However, the exact date of the call letter change to KYDO is not specified in the provided search results. For more detailed information, it would be advisable to refer to the Wikipedia page on KYDO or other reliable sources that might have a record of such changes. The source URL for the Wikipedia page is: KYDO - Wikipedia.