How to deal with employee quitting

Donec eu dui condimentum, laoreet nulla vitae, venenatis ipsum. Donec luctus sem sit amet varius laoreet. Aliquam fermentum sit amet urna fringilla tincidunt. Vestibulum ullamcorper nec lacus ac molestie. Curabitur congue neque sed nisi auctor consequat. Pellentesque rhoncus tortor vitae ipsum sagittis tempor.

• 15+ years of industry experience designing, building, and supporting large-scale distributed systems in production, with recent experience in building large scale cloud services.
• Deep knowledge and experience with different security areas like identity and access management, cryptography, network security, etc.
• Experience with database systems and database internals, such as query engines and optimizers are a big plus.
• Strong fundamentals in computer science skills.
• Expert-level development skills in Java or C++.
• Knowledge of industry standard security concepts and protocols like SAML, SCIM, OAuth, RBAC, cryptography is a plus.
• Advanced degree in Computer Science or related degree.
• Ph.D. in the related field is a plus