You can restore an individual Exchange Online mailbox item to the location that it was backed up from.
From the navigation pane, go to Protect > Applications > Office 365.
The Office 365 apps page appears.
In the App name column, click the app that contains the item that you want to restore.
The app page appears.
On the Mailboxes tab, select the mailbox that contains the item that you want to restore, click Restore, and then click Restore messages.
The mailbox contents appear.
Select the item that you want to restore.
Note: To include deleted items, click the action button, and then select Include deleted items.
Click Restore, and then click Selected items.
The Restore options dialog box appears, with options for restoring to the original location already selected.
For if the message exists, specify what to do with existing items:
To not overwrite existing items, select Skip
To overwrite existing items, select Unconditionally overwrite. If the existing items have not been modified then they are not overwritten during restore.