If your client changes their email address, there are a few easy steps to follow to ensure that they still have access to their items on the client portal. 

To update your client's email address go to the Client page > Contacts tab.

Click the Edit button and update the email address, then click the Save button at the top of the page.

Once that's done click Resend activation email button. 

Your client will now be able to sign in with their new email address, without losing access to anything that was already uploaded up to the vlient portal.