Add this extension to your Google Account. [https://chrome.google.com/webstore/detail/rename-email-subject-by-c/miepnlkmnjdfcnkplikgackpobfmaifb?hl=en](https://chrome.google.com/webstore/detail/rename-email-subject-by-c/miepnlkmnjdfcnkplikgackpobfmaifb?hl=en)

Go through the steps and approve access for this extension. 

Choose an email you would like to rename.

This is an awesome extension for Gmail. It allows you to rename any email. It's helpful to put in keywords for easy searching. 