I was able to get the CR's data, but I'm still struggling to find the changed fields/attributes (e.g. postal code changed).
CR's data:
DATA:
lo_gov_api TYPE REF TO if_usmd_gov_api,
lt_data_all TYPE usmd_ts_entity_data_all.
TRY.
cl_usmd_gov_api=>get_instance(
EXPORTING
iv_model_name = 'BP'
RECEIVING
ro_gov_api = lo_gov_api
).
lo_gov_api->if_usmd_gov_api_cr_data~get_crequest_data(
EXPORTING
iv_crequest_id = '000000000270'
IMPORTING
et_entity_data_inactive = lt_data_all
).
CATCH cx_usmd_gov_api. "
WRITE: '...'.
ENDTRY.