Is your guest asking for some accommodation or are you assuming there is a need, @Sherry128? Unless your listing includes that you are wheelchair accessible which also means you meet ADA regulations, you are under no obligation to make an accommodation. Now, I have had friends in wheelchairs stay at my place and they did fine, but I would not be able to say I meet ADA regulations. Perhaps if you have the conversation with your guest, you can become more educated about how some wheelchair bound people are quite capable of handling their requirements on their own. That is my experience, anyway. If you feel their is some implied liability given the specifics of your listing, you should definitely have the communication and you should use the Air BNB messaging system. Let us know how this all comes out.