Below is an example of an email you can send to the person in charge of equity. Depending on how your company is structured, the right person to contact may be the CFO, COO, General Counsel, an HR person, or someone else:
I am looking into exercising my stock options. In order to understand the tax implications of exercising (if any, including Alternative Minimum Tax), I need to know the Fair Market Value ("FMV") of the company's stock based on the last board-approved 409A valuation.
Would you please share this with me so that I can move forward?