We have a customer who holds a joint account with us. This person also has someone appointed with POA, who is not the joint owner on the account. How would a situation like this best be handled?

If the POA is being invoked, I would ask that the joint account be closed and an account be opened solely for the principal by the attorney in fact. This will ensure accurate record keeping and create the audit trail needed to protect the AIF from allegations of impropriety.