Changing airlines is usually an exciting thing. With that likely comes a whole list of changes between the two companies, which need to be accurately updated in APDL as well.
You can use the Settings Checklist as a wizard to configure APDL for your new airline. In addition to covering most of the configuration changes you will need to make, it also includes some optional features such as importing known crewmembers and tail numbers for aircraft at that airline. You can find the Settings Checklist at the bottom of the Settings page. Alternatively, you can configure it yourself manually by adjusting the settings one at a time.
Settings Checklist does not update:
Duty rig, Trip rig, Duty period adjustments, Payroll settings, Position, Reserve Categories, and Regulations
To set up APDL for a new airline, first go to Settings > Airline and change all the settings appropriately. You'll want to adjust things like Duty rig, Trip rig, and duty period adjustments prior and after as they are applicable to the new airline.
Go through your aircraft types list and archive the old types to declutter the list if desired. Create your new aircraft type and set defaults as desired.
Make sure to change your personal crewmember card to reflect your new position and employee number, as well as clearing the crewmember defaults and resetting yourself to default FO (most likely).
Go through the Payroll settings and set those accordingly.
Position, Reserve Categories, and Regulations settings may need to be updated as well.
After that you should be good to go.