Maintain email domain when changing account

Maintain email domain when changing account

Hello, first of all I apologize, I do not speak English very well and I'm using a translator. Well, this is the situation:
A company wants to change hosting from zohomail to outlook. They are paying for a corporate account in zoho and they created a domain "CL" of the company. But now they want to create a corporate account in outlook, keeping the domain they owned in zoho. They are going to stop paying the zoho bill and fear losing the domain.
So, how can they be changed without losing the mail domain?
I'm attentive to your answers.