You can change the field label for a standard LCRM field through these steps:
  1. Click Setup
  2. In the Quick Find search bar, search for Rename Tabs and Labels
  3. Click Rename Tabs and Labels
  4. Click Edit next to Contacts
  5. Click Next
  6. Modify the desired field label
  7. Click Save
Note: Please note that this is a standard feature of Salesforce, and not LCRM. If you have additional questions or trouble changing this field label, please contact Salesforce Support