A denial based on an open OUI case from three years ago with no felonies and no other record is worth appealing, and the warden's office is exactly where that appeal needs to go.
The process is straightforward but the approach matters enormously. Write a formal letter addressed to the warden at MCI Cedar Junction. Keep the tone humble, respectful, and focused entirely on why granting the visit is appropriate rather than arguing about why the denial was wrong. Wardens respond to cooperation, not confrontation, and a letter that comes across as demanding or adversarial will get you nowhere regardless of how strong your case is.
In the letter, lay out the facts clearly and briefly. State that you were denied visitation, that your record consists of a single open OUI case from three years ago with no felonies, no warrants, and no connection whatsoever to your boyfriend's case or the facility. Emphasize your relationship to the inmate, why maintaining that connection matters, and what you bring to his support system and eventual reentry. Keep it personal and genuine without being emotional or excessive.
An open case rather than a conviction is also worth highlighting. You have not been found guilty of anything, and the facility is essentially treating a pending matter as a disqualifying fact before any legal determination has been made. A respectful version of that argument, made carefully in the letter, is legitimate and worth including.
Send the letter via certified mail so you have confirmation it was received. Follow up politely if you have not heard back within two to three weeks.