Your question is a bit unclear. For example, what is your app used for? Because which feature was rejected? Generally speaking, Apple will tell you in more detail what is wrong, how to correct it, or what information should be provided.

Does your app have any functions that can be used in combination with other peripherals? If that is the case, it may be more troublesome. Some people on the Internet said that you can record a video for use and send it, or mail the relevant hardware products. For specific instructions on what to do, you should contact Apple’s reviewers. Reply them directly under the rejected message, and you will receive a reply or someone will contact you by phone.