US-FAA14 CFR 107.71
Retesting after failure
Read the official ruleOfficial FAA regulation text (public domain)
An applicant for a knowledge test who fails that test may not reapply for the test for 14 calendar days after failing the test.
Verbatim text of a US Federal Aviation Regulation (public domain), reproduced for reference — not legal advice and not for navigation. A plain-English explainer may be added later; always rely on the current official rule linked above.