Correcting birthdates of less active members not in local unit

During tithing settlement I have two members who want to correct birth dates of their less active children. Am I correct in assuming the only way to do this is to get their addresses, locating their membership records, contacting that ward clerk and passing along the information? Or, can I just contact church headquarters and accomplish the same task.
An example is a 80 year old mother noticed the incorrect birthdate for her 56 year old daughter who is less active and lives in another city. Mom does not know exact address now (I can get it later this week, but wanted to do this right away).

You might try sending a membership request message through MLS. Provide the name, birth date, and membership # of the child, along with the corrected information. I would also explain the source of the information.