Option to edit category labels on Power BI Reports

Hello.
I am finding difficult to change a category label on a report am working on. Here's a brief description of my challenge.

The organization has different category of sales people - FIELD SALES and ACCOUNT MANAGERS. The proposed report is focused on Field, but the datasource captures both categories.

I have a created a custom column to pick just FIELD from the employee table. But when visualizing the report shows the other Category value and "Blank" as the name axis.

Please how do i change this to a more descriptive category label such as NON FIELD