Another step in the process

Columbia Social Security Office:
SOCIAL SECURITY
STROM THURMOND FED BLD
1835 ASSEMBLY ST
COLUMBIA, SC 29201

Phone Numbers:
Local Number (803) 929-7635
Toll-Free 1-800-772-1213
TTY(800) 325-0778

Office Hours:
MONDAY - FRIDAY: 08:30 AM - 03:30 PM
Except Federal Holidays

Map:

This is where I need to go to convert my SSN to an American citizen version. I guess they're different somehow.