If you have had a good first interview and want to follow up with the company and show your interest in the role and the position that you have been interviewed for then it might be an idea to inform them that if they are considering doing second interviews that you would be available and interested to attend.
Doing any kind of follow up after an interview or letter/application always shows that you are interested and enthusiastic towards the role that they have on offer so it is not a bad thing to do but also jogs their memories about you and your skills, especially when they have probably interviewed other people after you also.
If you are looking for how to write a letter to follow up and request a second interview, please see the below example which you can use as a guide. Use this letter example if you are going to ask a second interview.
Follow Up Letter Requesting a Second Interview
Mr. A. Employee
1, My House
Mrs. A. Manager
Interview for the role of XXXXX
Thank you for taking the time to see me for an interview on DAY, DATE AND TIME. I very much enjoyed meeting with you and hearing all about your company and the role that you are looking to recruit for.
I am very much interested in working for your company and feel that I would fit into the role and your company very well. My skills and experiences to date will be a good match for this role and I feel that I have a lot to bring with me.
I would be available to attend a second interview, should you wish to conduct second interviews and could attend at short notice. Please do not hesitate to contact me once you have completed your interviews in order that we can hopefully set something up.
Finally, thank you again for taking the time to see me, I very much appreciate it and look forward to hearing from you in due course.