As mentioned previously, the study will run itself, since the participants have all the necessary information to complete the session. As the submissions come in, the UX researcher can do a quick review to ensure that the participants completed the session as expected and provided meaningful comments.
If the results are not as insightful as was expected, there may be an opportunity to go back to the study participant and ask them to elaborate. If a follow-up is possible and desired, it is best to do this as soon as possible so that the study participants still have their experience fresh in their minds.