Making a part rotating around a specific point?

For example: I have a part and normally if I use CFrame to rotate it, it will rotate from it's center. But for this one I want it to rotate at a specific point (it could be inside the part or outside the part). So how do you do it?

Describe in image: https://cdn.discordapp.com/attachments/363124434602688514/412619951182970901/unknown.png