How do I change my birthday date with my amended birth certificate? How long does this take to do this in the system?

Hi. I assume that you're referring to correcting your birthdate in Social Security's records. What you'll likely need to do is apply for a corrected Social Security card. The whole process will likely take at least a few weeks. You can find more specific information on what you'll need to do on the following Social Security website: https://blog.ssa.gov/replacement-or-corrected-social-security-cards-duri....

Best, Jerry