If if you were sure you could do a job after an interview

[SingaSong12]

Interviewed for a position last week. Now feel that there is an important part of the job I wouldn't be able to do. I don't think I can learn on the job and it might be detrimental to the customers.
I've been completely honest about what I can't do - it's a stand alone job so there will be no training and no one to ask. They are interviewing more.

Would you phone up and explain you are withdrawing and why, or wait and turn down if offered the job?

If you genuinely think you couldn't do it and have been honest it seems unlikely they would offer it to you - I don't think there's much it would be impossible to learn though if you tried (plenty of online training for most things these days)

I think it's unusual to appoint someone who completely ticks all the boxes, so they'll be expecting to have to support you. If offered the job ask what support will be on offer before you accept if it's worrying you.