Dear Professor* [Last Name],
I hope this email finds you well. My name is [insert name}, a student in your [insert class name] class. I know in the syllabus it outlines your office hours are [insert office hours]. Unfortunately, I am not able to make those hours because of [reason for not being able to attend]. I was wanting to come by and discuss [what you want to discuss] and I was wondering if there was another time that you were available to meet. I am free [list windows of time that you are free]. Would any of these times work for you? If not, when might you be available?
Thank you in advance for your time and flexibility. I look forward to meeting with you soon.
*Use the title they use for themselves. If they haven’t specified, “Professor [Last Name]” is preferred.