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If the contact is not in the database, the cover letter does not show "To," "Company Name," etc. It would be a nice feature to be able to quickly customize this information. As it stands, the cover looks unprofessional without this data.
If this is not set, the cover sheet "To" value will default to concatenating the address book contact's "firstName" and "lastName" attributes for the address book contact where the "businessFax" value matches the request's "to.phoneNumber" value.