What forms do I need to bring a motion for pick up of my minor child in front of a Magistrate?

I am the court ordered residential parent. My son went for a visit with his father 2 months ago to a different county and he refuses to return him alleging I am a neglectful parent to wit he involved CPI. CPI conducted their investigation and indicate that there is no neglect. My request for emergency ex parte pick up has been denied due to the time elapsed. The reason for my delay in action was the belief that as co-parents we would resolve this without the court and a lack of communication from CPI as well as misinformation from various clerks of the court.