Transfer sales plan to md61

Dear Experts,

In my Scenario Sales Deptt. Update sales Scheduling Agreement in SAP By VA31 and then MRP is running & creating Planned orders .

Now We wants to change our Process ,

NOW Before MRP Run we wants to transfer Sales schedule to Demand management MD61 , Where we can manually change Production plan which is not equal to Sales delivery schedule .

To copy sales schedule , I am doing Edit > Copy Requirement > Sales Plan > Total sales

Here system do not copy plan and shows below given error

u201C No production plan exists for product group XYZ u201C

Please let me know that how to copy sales schedules in Demand management (MD61) .

Regards,

ashutosh