Trying to change date_placed_in_service using the FA Adjustment API

Dear All,

I am trying to use the FA Adjustment API to create a adjustment on assets,
What we would like is to change the date_placed_in_service and the amortization_start_date of a given asset to set it prior to the actual creation_date.
I've made a lot of research on My Oracle Support on this topic, and on this basis I've (tried to) developped the following code :
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 PROCEDURE FA_Adjustment_API(p_asset_id IN number) IS

--l_trans_rec FA_API_TYPES.trans_rec_type;

l_trans_rec FA_API_TYPES.trans_rec_type;