Whenever I meet with partners today, I feel empowered to voice my thoughts with a sense of purpose.

In 2009, after 11 months of working at Facebook, I was offered a role working for our Chief Operating Officer, Sheryl Sandberg. The opportunity offered unparalleled exposure to critical business issues and, at the onset, managed to inspire uncharacteristic uncertainty.

In my first week on the job, I was asked to join Sheryl for a partner meeting that included the CEO and COO of a major media organization. I was a bit nervous given that we hadn’t yet worked together. To prepare for the meeting, I gathered our sales and partnerships teams to learn everything I could about the media organization. I became an expert on the client's business model and devised several concepts for ways we could work together more effectively. As I briefed Sheryl, she peppered me with tough questions that I tried my best to address.

After all of my preparation, the day of the meeting finally arrived. As I entered the room, the many participants began to assemble around a large boardroom table. I quickly realized that there were not enough seats available for everyone, but my instinct was not to wedge myself in. Instead, I settled on one of the empty seats along the conference room wall. As I sat down, a knot instantly formed in my stomach. Should I have joined the executives at the table?

After the meeting, Sheryl pulled me aside and asked me why I had chosen a seat on the side of the room. I didn’t know what to say, other than there hadn’t been any room. She urged me to "lean in," to innately believe that as her right-hand associate, I had already earned my seat. I realized that it was my responsibility not only to work alongside Sheryl for the many meetings we would take together over the next two and a half years, but also to directly engage with our partners, build credibility and earn their respect. Every new interaction became an opportunity to speak up with confidence and conviction.

While this was the first lesson I learned while working for Sheryl, it proved to be one of the most important. Whenever I meet with partners today, I feel empowered to voice my thoughts with a sense of purpose. Sheryl's emphatic counsel continues to ring loud and clear: "Lean in. Sit at the table."  And so, I do.