If I understand you correctly, you are asking "How do I withdraw my Motion (petition) to modify visitation?
Has your ex-husband's attorney responded to the Motion "to clarify visitation." If so, we should contact the attorney and ask if he would stipulate to the dismissal of the Motion without prejudice (so you can file a similar motion in the future) and also stipulate that each party be responsible for their own fees and costs. That would be the simplest method.
If their has been no formal response, you simply file a pleading, that says you voluntarily withdraw your motion without prejudice.