As well as allowing subscribers to update their own details, by giving them access to the subscriber preference center, you can update their information yourself.
Update individual subscribers
You can add or update one person's details through their subscriber snapshot page. Note that there's a snapshot for every list a subscriber is on. So if someone is subscribed to three lists, they will have three unique snapshot pages.
If you have multiple lists and are not sure which list the subscriber is on, you can search for them across all lists.
On the snapshot page, click the Edit [Name] button to add or edit the subscriber's details, then click Save changes.
