14 CFR §61.49

1. (a)An applicant for a knowledge or practical test who fails that test may reapply for the test only after the applicant has received:
   1. (1)The necessary training from an authorized instructor who has determined that the applicant is proficient to pass the test; and
   2. (2)An endorsement from an authorized instructor who gave the applicant the additional training.
2. (b)An applicant for a flight instructor certificate with an airplane category rating or, for a flight instructor certificate with a glider category rating, who has failed the practical test due to deficiencies in instructional proficiency on stall awareness, spin entry, spins, or spin recovery must:
   1. (1)Comply with the requirements of paragraph (a) of this section before being retested;
   2. (2)Bring an aircraft to the retest that is of the appropriate aircraft category for the rating sought and is certificated for spins; and
   3. (3)Demonstrate satisfactory instructional proficiency on stall awareness, spin entry, spins, and spin recovery to an examiner during the retest.