def modify_luna_client(ClientArn=None, Certificate=None):
    """
    Modifies the certificate used by the client.
    This action can potentially start a workflow to install the new certificate on the client's HSMs.
    See also: AWS API Documentation
    
    
    :example: response = client.modify_luna_client(
        ClientArn='string',
        Certificate='string'
    )
    
    
    :type ClientArn: string
    :param ClientArn: [REQUIRED]
            The ARN of the client.
            

    :type Certificate: string
    :param Certificate: [REQUIRED]
            The new certificate for the client.
            

    :rtype: dict
    :return: {
        'ClientArn': 'string'
    }
    
    
    """
    pass
