Hi,
So - you have a QUERY parm entitled transactionkey and you need the value? Is this being generated from the 'Transaction Key' step at the start of the test?
You need to do a Property Transfer from this step, grabbing the transactionkey value from, I'm guessing the response of the initial step to pass the value onto the QUERY parm of the test step youre talking about.
Within your QUERY parm you would insert something like '${transactionkey#value}'
Have a look at the followings and come back if you still need help
https://www.soapui.org/docs/functional-testing/properties/transferring-properties/
https://www.soapui.org/docs/functional-testing/teststep-reference/property-transfers/
https://www.tutorialspoint.com/soapui/soapui_property_transfer.htm
cheers,
rich