Final answer:
The best course of action is for Dan to follow up with the hiring manager via email or phone.
Step-by-step explanation:
In order to move on to the next phase of the interview process, the best course of action for Dan, the NASM Certified Personal Trainer, is to follow up with the hiring manager via email or phone.
It is important to send a thank-you note to the hiring manager within 24 hours after the interview to show appreciation for the opportunity and reiterate interest in the position.
By following up, Dan shows enthusiasm and professionalism, and it also gives him a chance to express any additional qualifications or ask any questions that may have come up after the interview.