The screenshot above shows the History section of the Time and Billing Screen. By clicking on a blue hyperlink you can make adjustments to that field.
If you wish to edit bill and pay rates directly from the time and sales screen please make sure to choose the appropriate setting in the
general settings page After clicking the field you wish to alter, you can edit the entry and then save your changes.
Keep in mind that when you adjust bill rates you might affect the look of your invoice because different rates within the same group get totaled on a separate line.