Hi Vag,
In the same system we can use both ERP Vendor or Lean Vendor..As lean Vendor is also leads to ERP Vendor only ie only in the requester step you will be finding the difference between ERP Vendor and Lean Vendor.Once you have submitted Lean Vendor CR, In the next step it is same as ERP Vendor...
Now if you dont want to use Lean Vendor Change Request then just delete the Lean Vendor CR types from the MDGIMG and just keep only ERP Vendor CR types.Now it will create only ERP Vendor CR.
Thanks & Regards,
Ibrahim.