Hi Jurgen,
Thanks for the reply. I have the checked the document too. It did not explain about the negative scenario.
1. My Manufacturer part profile has MPN mandatory, change in MPN and AMPL are activated.
2. I have created a MPN material and assigned this to internal material number and I have entered my manufacturer part number given by the manufacturer.
3.In MP01 I have entered the MPN material and my vendor for each plant with validity period as we are using the same material in both the plants but procuring from two different vendors from the same manufacturer.
4. For my negative test, if I try to create a PO for the MPN material to any other vendor other than mentioned in MP01 , system is not giving me any error as " the vendor is not maintained in the list"
SS