Mass CMDB Relationship Updates

I've been working on building our CMDB and I'm wondering if there is a "replace" feature for relationship map updates?  For example, we upgraded the routers that support our machine room.  I have lots and lots of things the point to the old routers and don't want to recreate all those relationships.  Other than just renaming the old CIs (which I'm pretty sure is bad practice) is there a way to "move" all those relationships to the new router CIs?