Export-Mailbox

This command can be used to export mailbox data from one, or many mailboxes, to another mailbox or a PST file.  It can also be used to delete items in mailboxes.

TechNet Article on Export-Mailbox, also see "How to Export Mailbox Data", there are some great examples on the second link.

Usage:
Export-Mailbox -Identity <Source mailbox> [-IncludeFolder <Name of folder, tree, to export>] -TargetFolder <Folder in target mailbox where data will be saved to> -TargetMailbox <Mailbox to export data to>

• Note: Items in the users Dumpster, items they have deleted that have not been purged for the database, will also be exported.

In the TargetMailbox a new folder will be created in the format of "<TargetFolder>\Recovered Data-<source alias>-<date and time>"