BEGIN {
    uid=""
    summary=""
    related=""

    FS=":"
    printf("%s,%s,%s\n","uid","summary","related");
}

($1 == "BEGIN"){
    uid=""
    summary=""
    related=""
}

($1 == "UID"){
    uid=$2
}
($1 == "SUMMARY"){
    summary=$2
}
($1 == "RELATED-TO"){
    related=$2
}
($1 == "END" && uid != ""){
    printf("%s,%s,%s\n",uid,summary,related);
    uid=""
    summary=""
    related=""
}