What happens to a domain during a registrar change?

Question

Domain Name System

The registrar change period is 5-7 days, what will happen to the domain at this moment?
DNS is used by a third party, it does not apply to the old or new registrars.
There is a working site on the domain, even a minute unavailability is undesirable.

Answer 1

Considering that you are not alone in the important stability of the site, they should go through everything as follows:
1. There is a period of registrar change (5-7 days according to your data). At this time, the site works on the part of the registrar from which you are moving.
2. Change of registrar. Short period, very short when the data changes.
3. Your domain is now with another registrar. Accordingly, if you are doing everything right and have already agreed with the new registrar. That process will pass without overlays and you will not even notice it.
I wrote it down so you can understand. In fact, everything is much simpler. You will not even notice the registrar change, as it is automated. If you do everything right, then the registrars also know that you do not want to see a broken site. So don't worry.
A week period does not mean that some programmers will be working on the site during this time and it will be unavailable. It's just an application review period or just a technical delay.

Answer 2

Thank you!
Yes, intuitively, all this is clear, but I would like a link to some kind of resource or regulation, so as not to guess, but to be sure.