Optional
When the message is sent to amend a guarantee, this field specifies the date of the amendment.
When the message is sent to request the Receiver to amend a guarantee, this field specifies the date of the request for the amendment.
Date must be a valid date expressed as YYMMDD (Error code(s): T50).
In the absence of this field, the amendment date or request for amendment date of the guarantee is the date on which this MT 767 was sent.