What happens if a patient has been in remission for leukemia and there is a possible reoccurence. How do we assign icd 9?

Unusual question. Newly diagnosed leukemia has ICD-9 code ending in .00 (acute lymphoblastic leukemia is 204.00 for example). Acute lymphoblastic leukemia in remission is 204.01. Acute lymphoblastic leukemia in relapse is 204.02.