(23:43:55\[D@DeCoBox15)
[~]$ cat input
Joe Smith jsmith 43234 bill1;bill2;read;read2;schedule
Andy Summers asummers 11232 bill1;read
Beth McConnel bmconnel 43443 read;read2;schedule;bill
Susan Fowler sfowler 09332 bill1;read;schedule

(01:16:30\[D@DeCoBox15)
[~]$ cat mysolution
#!/bin/bash
    tr ";" "\n" < $1 | while read line; do
        if [[ $(echo $line|wc -w) -gt 1 ]]; then
            array=($line);
            echo "${array[*]}";
        else
            echo "${array[0]} ${array[1]} ${array[2]} ${array[3]} $line";
        fi;
    done

(01:16:54\[D@DeCoBox15)
[~]$ ./mysolution input
Joe Smith jsmith 43234 bill1
Joe Smith jsmith 43234 bill2
Joe Smith jsmith 43234 read
Joe Smith jsmith 43234 read2
Joe Smith jsmith 43234 schedule
Andy Summers asummers 11232 bill1
Andy Summers asummers 11232 read
Beth McConnel bmconnel 43443 read
Beth McConnel bmconnel 43443 read2
Beth McConnel bmconnel 43443 schedule
Beth McConnel bmconnel 43443 bill
Susan Fowler sfowler 09332 bill1
Susan Fowler sfowler 09332 read
Susan Fowler sfowler 09332 schedule

[~]$ time awk '{n=split($5,a,";");for(i=1;i<=n;i++){print $1,$2,$3,$4,a[i]}}' pxe > /dev/null

real    0m0.088s
user    0m0.000s
sys     0m0.031s

(23:49:50\[D@DeCoBox15)
[~]$ time ./tst > /dev/null

real    0m2.338s
user    0m0.391s
sys     0m0.516s