Is there a way to use the Contract Reference Number on PO header for approval condition?

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Is there a way to use the Contract Reference Number on PO header for approval condition?

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Hi Gurus-

Just want to check if, is there a way that we can use the Reference Number on the PO Header for approval?

Our scenario is that we want to create an approval that if someone initiated a Change Order and there is a value on the reference number (means there is a contract associated on this PO) we will route it to the contract owner for approval.

However as i check it seems that this field is not available on the purchasing approval task.