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Accessing a Delegated Email Account
When you are granted access to a delegated email account, you can access it by clicking on your profile picture or email address in the upper-right corner of Gmail. Choose the shared email address from the lower half of this menu and the delegated account will open in a new tab within your web browser.
The delegated email account will allow you to send and receive mail sent to the shared address and label or filter messages as you would in your own mailbox. Any mail organization that you perform (marking as read, replying, deleting) will be seen by all delegates.
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You will not be able to change the delegated account's password or account settings, or chat as the shared account.