A filter allows you to manage your incoming mail using Gmail’s filters to send email to a label, or archive, delete, star, or automatically forward your mail. 
Use this resource to Create rules to Filter Your Emails.
Here is an example on how to change a filter from "All Employees" to "All Staff
1. Scroll to the [All Employees] filter on the left side of Gmail
2. Click on the three dots on the right of the label [All Employees]
3. Choose Edit
4. Change label to [All Staff]