How to delete the Cloud account from a MacBook without losing data (contacts, notes, photos, etc.) on an iMac?

Thank you for your reply.

I have considered the procedure you suggest, but I would need further clarification.

This is a procedure to do in case I want to give my device to someone else to buy a new one.

However, I already have the two devices and want to give one (Mac Book) to my son. Both of them now have the same Cloud account that stores certain system applications and shares them on both (calendar, contacts, photos, memos, notes), because I needed them when I was working away from home.

If I deactivate the Apple ID from the Mac Book I lose the contents of the applications in my iMac. That's what I don't understand. I need to keep my addresses and calendar on the big Mac. It's like - sorry if I'm being goofy - if the Cloud that's active on the Mac Book acts as the main entity, as opposed to what's on the other device: once that's gone, everything's gone. I'd like to avoid that.