Most users know how to change field label names via Settings > Modules & Fields but if you want to change the name of a system defined field you can’t as there is no “edit properties” option. 

However with a simple hack you can edit any system defined field if you have the translation settings available. 

To accomplish this go to:

- Settings>Translations

- Switch On Translation Settings

- Export the file

- Edit via a text editor (save a copy of your original!!)

- Search for the system field name and edit

- Then save and re-import.

Obviously backup your original file first before importing! 

Hopefully helps!

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