From the agency panel you step into any of your clients' accounts with one click. From that moment the application behaves as if you were that business: you see its campaigns, its contacts and its results, and you can work normally.

It is a change of context, not a merge: whatever you do inside an account stays in that account. To move to another client you go back to the panel and step into the next one.

One client's data is never visible from another client's account, even when the same agency runs both.

You can only step into businesses linked to your agency; one that has closed its account is no longer available. Every time you step into a client's account it is noted in that account's activity log, so the business's own team knows when the agency has worked in it.