How to get out of a process with HH while also saving relationship

I'm currently in a process with a MF. Opportunity is for next year and in an industry I thought I liked. I had a call with one of my mentors who is very experienced in the industry and took a similar path as I did. Long story short I simply wouldn't take the offer if given to me. I want to drop out of the opportunity but also want to save my reputation with the HH as they engage in many clients I'm super interested in. I'm not sure if I should just be straight with them and tell them that its not the opportunity for me anymore, especially after I made extensive remarks about why I liked the role (which were genuine at the time). What should I do? Any insights would help a lot.