Hello Kelly
Thank you for your request.
Unfortunately it is not possible to make a correction. You have the possibility to rebook your ticket with the correct date of birth and refund the old ticket. Contact our Railservice here you can get your old ticket refunded.
0848 44 66 88 (CHF 0.08/Min) +41 51 225 78 56
Have a nice day
GiuseppeL