Topic "User Specific Settings lost upon account rename" a message from _RNK_

Hi,
I renamed my domain account's username and noticed that on the few entries in which I had user-specific settings I no longer have access to it (the user-specific settings are blank as if I'm considered a new user). Under Administration -> Users I can see my old account but can't rename it as the field is grayed out. Using SQL Server data source with domain accounts. Is there a way to simply rename my RDM user account? The SID for the account should have remained the same.
Fortunately this was only a few entries and I can recreate the settings if I need to.

Thanks