Inclusion Criteria:

          -  Participants must have histologically confirmed acute myeloid leukemia (AML) diagnosed
             per WHO criteria.

          -  Participants must have relapsed or refractory AML.

          -  Age ≥ 18 years.

          -  ECOG performance status ≤ 2

          -  Participants must have adequate organ function as defined below:

               -  Direct Bilirubin ≤ 1.5 × institutional upper limit of normal (ULN)

               -  AST (SGOT) and ALT(SGPT) ≤ 2.5 × institutional ULN, OR

               -  AST (SGOT) and ALT (SGPT) ≤ 5 × institutional ULN if elevation is a result of
                  leukemia

               -  Creatinine Clearance ≥ 60 mL/min/1.73 m2 (calculated via the Cockcroft-Gault
                  equation)

          -  The effects of LY3214996 on the developing human fetus are unknown. For this reason
             and because anti-cancer agents are known to be teratogenic, women of child-bearing
             potential and men must agree to use adequate contraception (hormonal or barrier method
             of birth control; abstinence) prior to study entry and for the duration of study
             participation. Should a woman become pregnant or suspect she is pregnant while she or
             her partner is participating in this study, she should inform her treating physician
             immediately. Men and women treated or enrolled on this protocol must agree to use
             adequate contraception prior to the study, for the duration of study participation,
             and 4 months after completion of LY3214996 administration.

          -  Ability to understand and the willingness to sign a written informed consent document.

          -  Ability to swallow and retain oral medication.

          -  Participants must have resolution of adverse events related to prior anti-cancer
             therapies to ≤ CTCAE Grade 2 or baseline

        Exclusion Criteria:

          -  Participants who have had chemotherapy, other investigational therapy, immunotherapy,
             or radiotherapy within 2 weeks prior to the first dose of study medication. ATRA
             treatment is permitted with no required washout if treatment duration was for less
             than 1 week. Hydroxyurea is allowed with no required washout. For participants with an
             absolute peripheral blast count > 20 K/µL, hydroxyurea may be administered up to day
             14 of protocol therapy with a maximum allowed dose of 6 g per day.

          -  Participants who have received oral tyrosine kinase inhibitors (TKIs) within 5
             half-lives of the first dose of study medication.

          -  Participants who have had major surgery within 4 weeks prior to the first dose of
             study medication.

          -  Participants who have had a prior stem cell transplant (SCT) within 90 days prior to
             the first dose of study medication. Additionally, participants having undergone prior
             SCT must be off calcineurin inhibitor therapy for at least 28 days prior to the first
             dose of study medication.

          -  Participants with active > Grade 1 acute or chronic Graft v. Host Disease (GvHD) who
             are receiving immunosuppressive therapy other than prednisone. Use of prednisone is
             permitted only if participants have been maintained at a steady dose of < 20 mg/day
             for at least 5 days prior to the first dose of study medication.

          -  Participants with known active CNS leukemia involvement. Participants with no known
             history of CNS leukemia are not required to undergo lumbar puncture (LP) for trial
             eligibility unless the participant is symptomatic as judged by the treating
             investigator. Participants with a history of CNS leukemia involvement are eligible
             provided that the CNS disease has been adequately treated and cleared prior to study
             enrollment as judged by the treating investigator.

          -  History of allergic reactions attributed to compounds of similar chemical or biologic
             composition to LY3214996.

          -  Uncontrolled intercurrent illness including, but not limited to: ongoing or active
             infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
             arrhythmia, or psychiatric illness/social situations that would limit compliance with
             study requirements.

          -  Pregnant women are excluded from this study because LY3214996 is an agent with the
             potential for teratogenic or abortifacient effects. Because there is an unknown but
             potential risk for adverse events in nursing infants secondary to treatment of the
             mother with LY3214996, breastfeeding should be discontinued if the mother is treated
             with LY3214996. A negative serum pregnancy test is required for women of childbearing
             potential prior to study entry.

          -  Participants who are known to be seropositive for human immunodeficiency virus (HIV)
             or hepatitis B or C. Testing is not required for eligibility.

          -  Participants with a history or findings of central or branch retinal artery or venous
             occlusion with significant vision less, or other retinal diseases causing visual
             impairment as determined by an ophthalmologist.