How can I file for the custody of my kids if they live in a different state with their dad?

How can I file for the custody of my kids if they live in Arizona and I live in California? Their dad has sole custody, but I still have my rights.

If the father was awarded sole custody by a court and lives in a different state, I’m not sure you have any “rights” that you could seek to enforce for the purpose of wresting custody from their father.

What rights do you believe you hold that would entitle you to change of custody?