Hello, below is a case where a person has 2 rows of data and and 2 different values for the variable lx_item_id_rc on the same date (dos_rc). I am trying to identify all participants in the dataset that more than 1 value for lx_item_id on the same date. Suggestions are really appreciated.

n1 enc_id lx_item_id_rc lx_item lx_item_value class dos_rc
60 276429554 429 STAGE II (CHECK ALL THAT APPLY) General Conditioning 2) Stage 2 02may2017
70 276429554 428 STAGE 1 (CHECK ONE) Stabilization 1) Stage 1 02may2017