Frequently Asked Questions - Finger printing

FP or fingerprinting is a part of immigration and non immigrant processing.

Criminal History Summary Checks - FAQ's
1. Does the FBI accept personal checks, business checks, or cash? 2. Do you have procedures for expeditious handling? 3. Where can I get my fingerprints taken? 4. What if my fingerprints are continuously rejected? 5. Can I use the fingerprint card I download from this site? 6. Will my fingerprint card be returned? 7. How do I notify the FBI if my address has changed since I submitted my request for my Criminal History Summary or if I want to verify my correct address was submitted? 8. Does the FBI provide apostilles*? 9. How do I challenge my FBI record? 10. How can law enforcement entities request certified copies of fingerprints and/or Criminal History Summary information?
AOS interview next week, mother in India on AP
I am a US citizen, had applied for my parents GC in October 2009. Mom underwent fingerprinting three times here, but did not get her AOS done in time. End of last year my father (who got his EAD and AOS smoothly) had emergency heary bypass here, and then they had to leave back for India for more tests. Mom left on AP. Subsequently I wrote a letter to NBC, MO to ask them to expedite my mothers case. Yesterday I received a letter stating that she has go to Philadelphia USCIS office next week for "Completion of application to register for Perm residence." Mom is in India now.

You need to contact USCIS customer service for guidance. Definitely put something down in writing that you are requesting a rescheduling. Maybe asking your Congressman's assistance is the best way to go for rescheduling.