Hello Ana,
An agent who is not part of a queue should be able to respond to an email. However, there is an important distinction to note: An email interaction remains in the workgroup queue unless a non-member of the workgroup picks it up. If a non-member of the workgroup picks it up, it disappears from the workgroup queue.
So while you can respond to these email interactions as a non-member, picking them up will remove them from the original workgroup's queue.
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Jason Kleitz
Online Community Manager/Moderator
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