If any slave of Allah supplicate when he afflicted with a calamity -

إِنَّا لِلَّهِ وَإِنَّا إِلَيْهِ رَاجِعُوْنَ، اَللَّهُمَّ أْجُرْنِيْ فِي مُصِيْبَتِيْ وَأَخْلِفْ لِي خَيْرًا مِّنْهَا

Innaa lillaahi wa 'innaa 'ilayhi raaji'oon, Allaahumma'-jurni fee museebatee wa 'akhliflee khayran minhaa

We are from Allah and unto Him we return. O Allah take me out of my plight and bring to me after it something better. Umm Salama (RA) reported Allah's Messenger (ﷺ) as saying: If any Muslim who suffers some calamity says, what Allah has commanded him - (The dua is mentioned above) Allah will give him something better than it in exchange.

Reference: Muslim: 918