You can reset your password at https://mp.lesley.edu/ if you have set up your password profile and can answer your profile questions. You click on the Reset my Password section of the page and answer the 3 questions. Once you have done that, you can reset the password to one of your choosing, or have the system generate a new password for you.
If you haven't set up a password profile, or can't remember your answers, then contact IT at firstname.lastname@example.org, or call 617-349-8770, and press option 2. IT will reset your password to the default, and then you will be able to change your password.