Is the patient scheduled for pre-screening colonoscopy visit and during the visit a separately identifiable E&M service is performed that is completely unrelated to the colonoscopy, if so then you could potentially bill a preventive E&M and medical E&M.
Not all insurance companies cover the pre-screening colonoscopy visits, some will cover them with the preventive E&M codes 9938x-9939x, and some will cover the visit with HCPCS S0285- Colonoscopy consultation performed prior to a screening colonoscopy procedure, and some don't cover these visits at all. Medicare of course doesn't cover 9938x-9939x and S0285, and I'm not certain if they cover these pre-screening colonoscopy visits as there doesn't appear to be any codes that can be billed for this service that Medicare covers. You cannot bill a medical E&M code 99202-99215, because these codes are for the evaluation and management of a patient problem, not for screening or preventive services for patients with no symptoms or complaints.
Another thing to consider is that some insurance companies limit the number of preventive E&M visits 9938x-9939x per year and if so, you may find that the patient has already used this benefit and any claims your office submits may be denied as the benefit maximum is exceeded.
If you search the phrase "colonoscopy office visit" you will find numerous posts regarding this exact question in terms of pre-screening colonoscopy visit portion of your question.