You shouldn't simply rename an existing Cause. Here's why...

Let's use the example of "General Fund" as the exisiting cause and say you want to change it to "Back to School Bash". If you simply rename the exisitng cause, any data history associated with the General Fund cause will be combined with any data for Back to School Bash.

To avoid this, simply disable the "General Fund" cause, and create a new cause called "Back to School Bash". That way all of your data will be kept separate and reflect accurately in your records.