MicroStation Script

I’m trying to run a script that detaches a reference file.  However, there are multiple attachments, and I only want to detach the one without a logical name. 

I can detach any with a logical with reference detach 476002_3B_BR006_17.dgn [logical name].  But when I try reference detach 476002_3B_BR006_17.dgn it detaches all of those that match the file name.  reference detach 476002_3B_BR006_17.dgn “” doesn’t work either.

Any ideas?

Thank you!