How to convert all contact email addresses to lowercase in Eloqua?

Hello,

I would like to convert all uppercase letters in contact email addresses to lowercase in Eloqua.

I tried uploading a contact file with all email addresses in lowercase, but the contacts were not updated.
I confirmed that I can manually edit each contact’s email address one by one, but I’m looking for a way to update them in bulk.

Is there any recommended method or tool in Eloqua to automatically convert or bulk-update all contact email addresses to lowercase?

Thank you in advance for your help.