You can edit the Status Name, but you will need to check the below scenarios before editing the status name.

• You can edit only the Firm Specific Status (FSS) and not Default Status (DS).
• You are not able to edit a Status that is being used. So first, you need to move all tasks out of the Status, once there are no tasks in that Status you can edit it.
• The Status should not be mapped, using the Manage Workflow Mapping utility. If the Status is mapped, you can see the "Y" symbol under mapped column on Manage Workflow Statuses utility.To edit the task, please remove the Status from the mapping on Manage Workflow Mapping utility. 

Edit the Status Name: 

1. Click on the Utility Gear  on the My View Page. 
2. Go to Setup Utilites > Manage Workflow Statuses utility. 
3. Select the status(highlight) and scroll up. 
4. Click on Status Name field and then edit the name of the status. 
5. Click "Update"

Note: You can only enter 50 characters (Alpha-Numeric) while adding the status for the specific category under the Manage Workflow Statuses Utility.