One very important aspect to each episode is the table-read. A table-read is an organized reading of the entire script where the speaking parts are conducted by all the actors and actresses. This reading is usually done "cold," meaning none of the actors have been able to rehearse their lines in advance.
This can allow Directors, Producers, and the rest of the creative team to determine if anything from the script needs to be adjusted before production begins. This can include adjusting plot lines, dialogue, or individual scenes.