There are many reasons why a job seeker might be willing to accept a position at a lesser compensation level. One obvious reason: a lower salary is preferable to unemployment, especially so if you are currently out of a job, suspect your job may be in jeopardy, or have been given a soft message that it is time to start looking elsewhere. Unfortunately, imminent unemployment is not a compelling reason for a future employer to hire you as employers tend to be more focused on your long-term commitment and desire to be at the firm/company.
So how do you convey to the hiring manager(s) that you are committed to the opportunity and not desperate or seeking a stopgap solution?
We recommend highlighting the inherent opportunities for growth, learning and experience that the new position affords. For example, it might be that the new position would allow you to expand your practice knowledge and gain experience in an area that you have long regarded as interesting, or complimentary to your current practice. Perhaps you would be given opportunities to assume greater responsibility, or work with certain partners and business people, or enhance your exposure to certain industries. People seek out jobs that pay less all the time, for myriad reasons. As long as your reasoning is sound and well thought out, you should be able to make a compelling case for yourself.