Who should I address a cover letter if I don't have the info

Who should I address a cover letter if I don't have the info?
I'm handing in today my resume in an interview I have. But I don't know who will be interviewing me nor the address of the place (because it's in a hotel conference room or something like that). Who should I address the letter to? Dear Human Resources Representative? Also, what address would I write? or I just omit it? PS. I think Dear Ma'am or Sir it's too sexist as I could write Dear Sir and it's a woman who interviews me.
Administrative and Office Support - 4 Answers

Random Answers, Critics, Comments, Opinions :
1
First, research the company on the web and see if you can find the officers listed. If not, make a call to the company and ask whoever answers the phone if they know the name of the person conducting interviews today. Explain your dilemma only if they ask why you need to know. Otherwise use a generic title such as HR Rep, Manager etc. As to the address, use the company name and the city and state only.


2
Write Dear Mam/Sir; Get company name and some kind of address from somewhere even if it is the street address of whole company.


3
Another idea is to address it to "Hiring Manager". Even though I am HR, I also value to ability to get past HR.


4
I was advised by a recruiter to address the letter simply Dear Manager,