The earnings limit for those like you who have not yet reached the full retirement age is $1,310 per month, or $20 more per month than in 2014. If you exceed this limit, you’ll lose $1 of benefits for each $2 of benefits over the limit.
On Form 1040X, you may file an amended return within a three-year period to claim a refund or correct a mistake made on an original or previously amended return.