Change a user’s ActiveSync policy back to take the Org default EAS policy…
By default, at the point of creation a user is created to take whatever is the organisation’s default policy. When this is changed to a specific EAS policy the ActiveSyncMailboxPolicyIsDefaulted property is changed to False. This can be annoying in the future as you may want them to revert back to the default policy for the organisation. This won’t happen is they’ve previously been assigned a specific EAS policy.
To set the ActiveSyncMailboxPolicyIsDefaulted attribute back to true, just use the following command:
Set-CASMailbox -Identity "USER-IDENTITY" -ActiveSyncMailboxPolicy:$null