It's not possible to rename system fields.
The only option you have in regards to any changes, is to translate them.
As described here:
As far as i can see, it is not possible to translate field in cloud. So which language the fields are shown in, will depend on the language chosen on setup.
I did find a feature request which describes what you're after.
You can go in and vote for it and watch it to get updates:
Hello Insight users, As part of our (Mindville's) acquisition by Atlassian, our training team is looking to build some new Insight training materials. It would really helpful if you can ...
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