If you want to remove a guest account from an external organization's tenant, you need to have the appropriate permissions and access to that specific organization's administrative tools or user management system. The exact steps to remove a guest account will depend on the specific platform or system being used, such as Microsoft 365, Google Workspace, or other cloud services.
To remove a guest account, typically, an administrator or someone with administrative privileges in the external organization's tenant would log in to their account, access the user management dashboard, locate the guest account they want to remove, and then proceed with the account deletion process according to their organization's policies and procedures.
Keep in mind that removing a guest account from an external organization's tenant should be done carefully, and you should ensure that it aligns with your organization's policies and any applicable data privacy regulations. If you don't have the necessary permissions, you should contact the appropriate administrators in the external organization to request the account removal.