7. A computer readable medium containing computer-executable instructions for a processing, the computer readable medium comprising: computer-executable instructions for inputting a first process description document; computer-executable instructions for performing a service in accordance with a procedure written in the first process description document including first, second, third and fourth description parts, the first description part describing a receiving processing for receiving data from a client via a network and a service processing for performing the service, the second description part describing a call processing for calling a second processing apparatus which is connected to the network and provides a second web service, the third description part describing a conversion from a variable used by the second processing apparatus to a variable used by a third processing apparatus, and the fourth description part describing a call processing for calling the third processing apparatus which is connected to the network and provides a third web service; computer-executable instructions for generating a second process description document including the first and fourth description parts by deleting, from the first process description document, second and third description parts; and sending the second process description document to the next processing apparatus described in the deleted second description part.
7. A computer readable medium containing computer-executable instructions for a processing, the computer readable medium comprising: computer-executable instructions for inputting a first process description document; computer-executable instructions for performing a service in accordance with a procedure written in the first process description document including first, second, third and fourth description parts, the first description part describing a receiving processing for receiving data from a client via a network and a service processing for performing the service, the second description part describing a call processing for calling a second processing apparatus which is connected to the network and provides a second web service, the third description part describing a conversion from a variable used by the second processing apparatus to a variable used by a third processing apparatus, and the fourth description part describing a call processing for calling the third processing apparatus which is connected to the network and provides a third web service; computer-executable instructions for generating a second process description document including the first and fourth description parts by deleting, from the first process description document, second and third description parts; and sending the second process description document to the next processing apparatus described in the deleted second description part. 8. The computer readable medium according to claim 7 , wherein, when the processing is performed, callback information is added to the second process description document, where the callback information is used to transmit information about a final result of the procedure to the computer.