Document email verification for EMUs (#51813)

Co-authored-by: Ben Ahmady <32935794+subatoi@users.noreply.github.com>
Co-authored-by: Siara <108543037+SiaraMist@users.noreply.github.com>

content/account-and-profile/setting-up-and-managing-your-personal-account-on-github/managing-email-preferences/changing-your-primary-email-address.md

@@ -1,6 +1,6 @@
 ---
 title: Changing your primary email address
-intro: You can change the email address associated with your personal account at any time.
+intro: To change your primary email address, you'll add a new email, then delete the old one.
 redirect_from:
   - /articles/changing-your-primary-email-address
   - /github/setting-up-and-managing-your-github-user-account/changing-your-primary-email-address
@@ -15,11 +15,14 @@ topics:
   - Notifications
 shortTitle: Primary email address
 ---
-{% note %}
 
-**Note:** You cannot change your primary email address to an email that is already set to be your backup email address.
+You can change the email address associated with your personal account at any time. You cannot change your primary email address to an email that is already set to be your backup email address.
 
-{% endnote %}
+{% ifversion ghec %}
+
+[!NOTE] This article **does not apply** to {% data variables.enterprise.prodname_managed_users %}. To change your email address as a {% data variables.enterprise.prodname_managed_user %}, contact the administrator for your company's identity provider (IdP). Your primary email address is the first one assigned to you in the IdP.
+
+{% endif %}
 
 {% data reusables.user-settings.access_settings %}
 {% data reusables.user-settings.emails %}

content/account-and-profile/setting-up-and-managing-your-personal-account-on-github/managing-email-preferences/verifying-your-email-address.md

@@ -15,7 +15,8 @@ topics:
   - Accounts
 shortTitle: Verify your email address
 ---
-## About email verification
+
+## About email verification{% ifversion ghec %} for personal accounts{% endif %}
 
 You can verify your email address after signing up for a new account, or when you add a new email address. If an email address is undeliverable or bouncing, it will be unverified.
 
@@ -42,6 +43,16 @@ If you do not verify your email address, you will not be able to:
 
 {% endwarning %}
 
+{% ifversion ghec %}
+
+## About email verification{% ifversion ghec %} for {% data variables.enterprise.prodname_managed_users %}{% endif %}
+
+If you are a member of an {% data variables.enterprise.prodname_emu_enterprise %}, your email address is considered unverified if it is used as a verified email by another account on {% data variables.product.prodname_dotcom %}. To verify the email, you will need to unverify the email address for the other account, then verify it for your {% data variables.enterprise.prodname_managed_user %}. See "[AUTOTITLE](/account-and-profile/setting-up-and-managing-your-personal-account-on-github/managing-email-preferences/changing-your-primary-email-address)."
+
+Having an unverified email address does not affect most actions you can take on {% data variables.product.prodname_dotcom %}. However, it may prevent you from accessing some third-party {% data variables.product.prodname_github_apps %} and {% data variables.product.prodname_oauth_apps %}.
+
+{% endif %}
+
 ## Verifying your email address
 
 {% data reusables.user-settings.access_settings %}
@@ -68,6 +79,16 @@ If you click on the link in the confirmation email within 24 hours and you are d
 1. Sign in to your personal account on {% data variables.location.product_location %}.
 1. Click on the verification link in the email we sent you.
 
+{% ifversion ghec %}
+
+### Email is already verified by another user
+
+If you see the error message `Error adding EMAIL: Email is already verified by another user`, you must either unverify the email for the other account before proceeding, or choose a different email address to verify.
+
+To unverify an email address, delete it in your email settings, then optionally re-add it without verifying to keep any commits linked to your account. See "[AUTOTITLE](/account-and-profile/setting-up-and-managing-your-personal-account-on-github/managing-email-preferences/changing-your-primary-email-address)."
+
+{% endif %}
+
 ## Further reading
 
 * "[AUTOTITLE](/account-and-profile/setting-up-and-managing-your-personal-account-on-github/managing-email-preferences/changing-your-primary-email-address)"