I don't have the answer, just the same problem. :/ Nor can I change the name of a calendar I have (I want't it to be called "Hem" ("Home")). Also, if I try to create a new one with "Hem" as the name, it's just ignored and named "nameless".
While I was writing the text above I tested out some random stuff and now I actually think I have the answer. For obvious reasons you can't have the same name for two calendars. What I've discovered is that the reminderlists seems to go as calendars as well. So if I have a reminderlist called "home", I can't name a calendar "home". This is very confusing!
So to solve the problem you have to show the reminders (++T), click "reminder" up in the right corner and when the window with all the reminderlists pop up, you rightclick and delete the list that have the name you want for the calendar. BUT BE CAUTIOUS, remember that you may have reminders in that specific list you're going to delete.
This is the solution for my problem and I hope it is for you to!
I share the same problem - some calenders are content to have a common name in both the "Reminders" and the daily diary, but when I create a new callender there is a refusal to share the name and defaults in one of ther formats to "unidentified". I have followed Thunderthigh's advice above (many thanks) and it works - I have the same description in each database with the exception of a full stop in one of the formats to distingusih. Why this should be so difficult I do not know!