In this method, a call is opened and material is ordered specifically for that call. Tying the MO to the call has the advantage of making all the tools inside Call Activity Recording available for managing the MO. In some business situations, this explicit connection between service inventory allotments and call history is required for legal or contractual reasons. In other cases, the business simply prefers this method, or it is the easiest, most economical way to supply engineers and account for service costs.

When a call is specified, the engineer defaults to the one currently assigned to the call, but this value can be overridden. If no engineer is assigned to the call, you must select a valid engineer to receive this order. If shipments for this MO have already been processed, the engineer cannot be modified.