The warden is making a judgment call, and the letter needs to give them a genuine reason to make that call in your favor. Being strategic and honest about how you approach this matters.
The core policy behind the denial is the rule that inmates are not supposed to have contact with people who have criminal cases pending or convictions on their record. To override that rule, you have to show the warden that the relationship and the visit are worth the exception.
Start by acknowledging your pending charges directly. Do not hide from them or minimize them. Explain the circumstances as clearly and honestly as you can. If there are mitigating factors, state them. If you have expressed remorse in the legal process or taken steps toward resolution, mention that. The warden is reading between the lines to assess whether you are being straight with them. Anything that feels evasive or spun will work against you.
Then make the affirmative case for why the visit matters. What is your relationship to the inmate? How long have you known each other? Why is maintaining this connection important for their reentry and well-being? The warden cares about the inmate's stability and the facility's orderly operation. An appeal that frames the visit as beneficial to the inmate's behavior and reentry prospects lands better than one focused only on your own desire to visit.
Be respectful, be concise, and be genuine. Wardens review a lot of these letters and can tell the difference between someone sincere and someone who is saying what they think the warden wants to hear.