Can I migrate to a personal Apple ID?

What is the objective here? Are you trying to change the email address on a given account, or are you trying to change the account on the device itself. In other words, sign out of one account and sign into another?

Here's how you change the email address you use for your Apple ID:

1. Go to https://appleid.apple.com and sign in.

2. In the Sign-In and Security section, choose Apple ID.

3. Enter the email address that you want to use as your Apple ID.

4. Choose Change Apple ID.

5. If you changed your Apple ID to a third-party email address, check your email for a verification code, then enter the code. Learn what to do if you didn't get the email. --> If you didn't receive your verification or reset email - Apple Support

6. If you use services like iCloud or Messages to share with friends and colleagues, sign in to those services with your updated Apple ID. --> What to do after you change your Apple ID or password - Apple Support

For more details and how to do this if you have a mobile number ID, see the document Change your Apple ID - Change your Apple ID - Apple Support

It's also not clear to me if you are changing to a different account, if you also want some data from the old account.

If you have signed into the ID on two devices then when you sign out of one ID and sign in with a different one it asks you in most cases if you wish to retain the data from it on your device.

Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac --> Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac - Apple Support

If another Apple ID is signed in you may need to enter the password for that ID to sign out of that ID first.

Click on this link to learn how to 'Sign in with your Apple ID' --> Sign in with your Apple ID - Apple Support