Available is a Boolean property that indicates if SMTP Enhanced Status Codes are used or significant in the SMTP reply. 

Changing the value in Available to True causes the StatusClass to be set to CLASS_DEF, and both Subject and Detail to be set to NODETAILS. 

The default value for Available is AVAIL_DEF as assigned in Create. 

Available is updated automatically when writing a value using ReplyAsStr. Available contains True when a non-blank value passes the validations required for the StatusClass, Subject, and Details properties. 

Use the NumericCode or Text properties when Available is False.