You can file a contempt motion but you may have a problem proving your case because a child's out of court statements are, with a few exceptions, inadmissible. Contempt actions are not very easy to maneuver through the legal system an I recommend that you hire a lawyer to assist you. It may be possible that there are other solutions to consider.
Any non-compliance with a court order is contempt. You can file a Verified Motion & Affidavit for Citation for Contempt of Court. The forms and instructions can be found online at the Colorado State Judicial Branch website (see link). You will need to state the facts of the contempt and also provide a copy of the order that gives you first right of refusal.
Yes, you can file contempt. It is not a simple process, however, and can be frustrating as the Court will often do little more than restate their prior orders if this is the first time it has been brought up before the Court. Often contempt has to be pursued several times before the judge reaches the point of imposing serious sanctions.
Another option, if you can show that this is happening regularly, is to file for modificaiton of parenting time. The purpose of the first right of refusal is to allow the child to spend time with you when the other parent is unavailable. If this is a regular occurance, perhaps the parenting time orders should be revisited.
You can reach Harkess & Salter LLC at (303) 531-5380 or info@Harkess-Salter.com. Stephen Harkess is an attorney licensed in the state and federal courts of Colorado. This answer is for general information only and does not create an attorney client relationship between Stephen Harkess or Harkess & Salter LLC and any person. You should schedule a consultation with an attorney to discuss the specifics of your legal issues.