"how do you deal with a complaint of racism"

[strictlymomdancing]

So I am currently working as an equality and diversity adviser in a huge organisation. We have lots of departments and an E&D adviser in each department basically.
due to discrimination (yes - ironic that me as an E&D adviser is getting discrimination) I am looking for another role.
I had an interview today for a smaller employer (only 500 people compared to our over 6000) for an E&D adviser role.
And I feel I royally fucked it up. I should have been better prepared, I know.
They asked me:
"what would you do if a foreign member of staff came to you to report racist behaviour from a colleague?"
and I stumbled over my answer. (PS yes I did question the wording, which I think pissed them off)
Anyway, I should know the answer to this, right?
But as I said above, in my organisation, HR have an E&D adviser, so any complaints like the above go straight to him. My E&D role is to do with customer complaints so external rather than internal.
This role I applied for appears to want an E&D adviser for everything. Alarm bells were ringing admittedly before I went in to the interview as there was little information provided about the role, salary etc so I did feel a little misled into thinking it was a customer facing role when it appears to be a more administrative HR role.
Anyway I did try to answer it as best as I could and talked about working with HR, offering HR additional support and guidance, calling on the knowledge and expertise of my third sector contacts, conducting an investigation, offering awareness training etc.
How can I improve on this answer in future? What is a better answer to give?
Kicking myself. All other answers I was confident and prepared but this one threw me as its not what I currently do. As we are such a large organisation, people tend to go to their union rep or manager or to my HR E&D colleague - very rarely to me and I'd get my knuckles truly rapped if I stepped on someone's toes.
Anyway I don't think this is the role for me anyway. They want more than I do for less than I currently get paid. Feel annoyed that I wasted my time on a job that was not as described.
Will still be better prepared though.

Ok so first I am not an edi advisor.
I would take the person somewhere private and let them speak.i would acknowledge their upset and issue.i would let them know that I will document the discussion formally as this form of behaviour is not acceptable. I would ask the person if they are ok and show care. I would check if they needed to leave the workplace temporarily to reduce their immediate stress.
I would then report the issue to the potential perps manager for them deal with.
If I had to deal with it myself.i would discuss that it had came to my attention...
Then it may be a case of clarifying the exact words.
Do they believe this behaviour is acceptable?
It might end that the perp is moved away from the person. Or potentially warned to stay clear or further action could be taken.disciplinary in line with company policy.

Seh81, the problem with your answer is that you've assumed that the alkergatis true. You are correct to acknowledge their issue, of course. But you cannot assume guilt.

I think it's always best to stick with the company's policies and procedures and administer a bit of care to the accuser.

Ponoka7 thanks for your comment.
Yes deffo stick with the policy.by acknowledging the persons feelings and issue is by no way assuming this actually happened and the other person is guilty.
People who report difficult things need to feel they are fully listened to and the information shared is acknowledged. The edi person could even go as far as saying “i understand what your saying and see that your upset. I will be looking into this further”
(There’s always two sides to a story)
Thanks again for your reply