Users with the appropriate permission can configure an application which includes enabling and disabling apps, adding lists, making fields required, setting default values, changing the numbering system and modifying lookup lists. To change lookup values:

1. Navigate to the appropriate app
2. Click the Configure button in the app options icon (shown below)

3. Click on the Lookups tab
4. Fort the attribute you would like to update, click the Override radio button (the configuration inherits from the project or area one level above the current project or area you are in.  Clicking override allows you to configure the project or area you are currently in and any sub-projects without affecting other projects or areas)
5. Select the appropriate lookup field and click the Edit icon 
6. Add, delete and re-order values as appropriate
7. Click the Ok button when done