stage ('echo variables'){
            agent {label 'a_server_name'}
            steps{
              load "path_to_file\abc.properties"

                echo "Hi"
                echo "slave : ${SlaveNode}"

                              //executes successfully

            }

stage ('Execute script'){
            agent {label "$SlaveNode"}
            steps{
                echo "This is executing script"

            }

  // fails with error : There are no nodes with the label ‘SlaveNode’