You can now sign in to your Zoho account in more than one data center (as secondary accounts).
Let's say you have signed in to a Zoho account which is signed up in the United States (US) data center (primary account) and you have a secondary account in Europe (EU). Now, if you try to access a service on Europe's data center, you will be taken to the sign-in page that will show your primary account as signed in. You can either just select it and you'll be signed in to your secondary account using your primary account's session or click Sign in with another account to sign in with a different account.
Do note that all the secondary accounts sign in will be done in the account's primary data center, which is the primary account. This means the primary account's credentials will be used to sign in to your secondary accounts, and when you sign out, you will be signed out of all the accounts (both primary and secondaries).

If third party cookies are blocked, the primary account details will not be shown in the sign-in page.