STEP 1 - Gather backups
The most important step in migrating a website is gathering its backups, which can be done as guided here: How to generate backups?
If you also want to migrate your emails, it’s a perfect time to do so before pointing/transferring your domain elsewhere. That can be done with the help of IMAP Sync tool
STEP 2 - Transfer/point domain
Now, when it comes to the domain, you need to check if the domain is registered with us or not. If it’s registered with us - you will need to transfer it away. On the other hand, if it’s registered elsewhere - you can just point it away.
STEP 3 - Restore backups
That’s it! The last thing to do is to restore your backups with a new provider.