A foreign posting is often a validation of your work. You have proven yourself and your company sends you abroad to earn your spores for further advancement in a global economy.
A move abroad is a great opportunity for more self-discovery as you and your family will have a chance revisit their roles and identities in a different cultural context. As you leave the familiar behind you get to discover new surroundings, make new friends, live a different life and get exposed to a new culture.
Change impacts people differently and how you handle it will determine how you perform in your new role. If you move countries with your partner/spouse and possibly children, it will also influence their experience of their new life.
I have worked and lived in five countries and on three continents. The first move from Europe to Asia involved just my wife and myself. We also experienced an intercontinental move from the US to Europe with three teens. It was exciting but we struggled. We were enthusiastic but we also cried a lot.
Coaching provides you with an opportunity to prepare and or work through your experiences of your posting once you have moved.