Hi Rolf,
Your question is not very clear. May be you explain what you want to achieve after getting first entry of table.
In your calling procedure you would make a call and bind the output table like this
call proc1 ( :input_param, output_tab);
On the returing output_tab you could just write something like
output_top1 = select top 1 * from :output_tab;
You could use this table for whatever processing you want to do further.
If you want to get values into some scalar variables that is also possible.
e.g
declare lv_column1 nvarchar(10);
select column1 into lv_column1 from :output_top1;
Thanks
Sagar