In order to rename theme words, you can use Loco Translate plugin.
Please see below the steps that needs to be followed:
1.Install Loco Translate plugin
2. Install wprentals-child-po.zip and activate it.
Go to Loco Translate – Manage translations and edit the en_us,po already given in child theme
— select the language that you have chosen in Settings-General
Search for the words that you wish to rename in child theme
— add the new words and save