SSRS Adding a column from a new table to the RDD

My task is to modify the RMA Form and one of the requests is to include the Customer Part Number (CustXPrt.XPartNum) on the detail line.

I added the new table and built a relationship with the RMA detail line:

However, I cannot find the XPartNum as a description field. When I run the report and query the query data created, the value is not passed into any of the report datasets. I would expect it in the RmaDtl dataset but it’s not there.

What am I missing?

Problem solved!
I had to change the Relation Type to “Output”.