It is necessary to build in cross-training and backup for each key role on the team. That way, you have one or two other people within the discipline that can step up to fill the position.

It's a good idea to have sessions where team members find out more about the roles of team members in other positions and departments. That can help to get a new team member up and running faster and facilitate collaboration and brainstorming.

As you cross-train team members, ensure to keep your talent bench deep. Then, when a high-impact team member leaves, another candidate can be ready to overlap and replace them.

Consider a clear plan on what you want the transition to look like in terms of content knowledge that you expect for the new leader to develop, the necessary individual relationships, and the most critical potential fail points for the project.

Capture enough information about why decisions have been made, the next steps, and who is accountable for them. Best practices include:

• Determine the frequency of the meetings for effective information-sharing and schedule them.
• Capture meeting notes, including the reason for the decision, the next steps, and the person responsible.
• Use uniform collaboration tools (Slack, Asana, Monday, etc.) to track project steps, progress, communication, and outcomes.
• Establish a communication hierarchy so the team has norms about where information can be found.

If you're leading a team and a key member is leaving, don't try to solve the issue by yourself. Instead, involve HR and a set of cross-functional peers. Look at what's required for the role and brainstorm about who could best fill the position. They may recommend someone you’ve never thought of.

Document the most immediate team needs and actions, and identify who can fill those roles. It may be possible to hire temporary or freelance help to fill gaps.

Team members may keep information to themselves if they feel some threat in the organisational culture.

Organisations should work to establish a culture of trust to help employees feel they can share knowledge. Part of trust-building is giving employees a sense of ownership and autonomy, so they feel valued.