Generating a report by using relationship as search criteria

I am trying to generate a report to show ONLY ECRs that have PR items linked to it. I first tried to test using a specific search for ECRs with PR-100006 attached, which should only return one instance, but it seems to have generated every ECRs in the system and spelled out every PR relationship when they exist instead of showing the one ECR that has a relationship with PR-100006.

<AML>

    <Item type="ECR" action="get" select="item_number">

        <Relationships>

            <Item type="ECR PR" action="get" select="item_number">

                <item_number condition="eq">pr-100006</item_number>

            </Item>

        </Relationships>

    </Item>

</AML> 

Can someone please show me how I would rewrite the AML so:

1. I can search on a relationships criteria 

2. I can generate a report to show ONLY ECRs that have PR relationships?