I don't know that there is a "correct" method for this; it's not as though it's a regular task that needs to be done. However, the following should work, if you don't mind losing all your data:
# mysqladmin drop horde
# cd /home/httpd/html/horde/scripts/db
# mysql < mysql_create.sql
# cd ../../turba/scripts/drivers
# mysql < mysql_create.sql
# mysqladmin reload