These instructions apply for removing members from an account, organization, or team, but the screenshots will only show removing members from a team. The steps will be the same for the account and organization levels.
The account owner, organization managers, and team managers can remove members from a team. The account owner and organization manager can remove members from an organization. Only the account owner can remove a member from an account.
You will see a confirmation popup :
Removed members will disappear from MEMBERS tab of current account, organization, or team.
Members that were removed from a team will still exist in the organization and account level, until someone remove them from organization or deletes them from account.
If a member exists in both a parent team and a child team, and you remove them from the parent team, then that member will still exist in child team.