Yes, if you are changing plans, visiting more countries (lucky you!) or have a layover in an additional country, it's very easy to add countries to your itinerary.

1) Go into your Trip Settings (the cog icon in the top right).

2) Select 'Destination', and then search for, and select, the additional countries you are visiting.

1) Select 'Edit Trip' (top right) on the Overview page.

2) Select 'Destination', and then search for, and select, the additional countries you are visiting.