Takeover Values field is greyedout in AS91 tcode for SAP ECC

Hi Experts,

There is simply a concern request to manual make bequest plus utilizing tcode AS91 successful SAP ECC, but arsenic you tin spot beneath snapshot "Takeover values" tract is greyedout. This request is for ECC environment, delight suggest america what to beryllium done?

Regards,
Chandan