Edward, you will need to use pitch bend to make the note flatter or sharper. If you don't have a pitch bend wheel or pitch bend/modulation (CC1) joystick you will have to manually insert one. This is done via the event list, however I use Sonar for this type of in-depth work so someone with either BiaB or RT event list skills will have to help you.

If you are not familiar with pitch bend this will either raise or lower a note or notes. The range is determined by the software/hardware that you are using. The most common range is two octaves but in many cases you can adjust this range in the software/hardware to whatever suits your needs, or example +/- 5 octaves or +/- 5 cents. You will be working in the cents area. If you already know this then I apologize for the redundancy.

Ps - another thought. If you have pitch correction software you might be able to correct the pitches. The problem here is the only one that I know of that really works for polyphonic instruments is Melodyne Editor and that one is expensive.

I just posted a selfie and all of the responses were get well soon!

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware