SQL> ed
Wrote file afiedt.buf

  1  with t as
  2  (select 1 id, 'act' state, 'std' sub_state , '01.01.2016' v_from,'01.02.2016' v_to from dual
  3  union all
  4  select 1 , 'pas' , 'wait' , '01.02.2016' ,'01.03.2016' from dual
  5  union all
  6  select 1 , 'act' , 'std' , '01.03.2016' ,'01.04.2016' from dual
  7  union all
  8  select 1 , 'act' , 'std' , '01.04.2016' ,'01.05.2016' from dual
  9  union all
 10  select 1 , 'pas' , 'wait' , '01.05.2016' ,'01.06.2016' from dual)
 11  ,tt as (select id,state,sub_state,to_date(v_from) d_from,to_date(v_to) d_to from t)
 12  --
 13  select id,state,sub_state, min(d_from) d_from,max(d_to) d_to from
 14  (
 15    select
 16      tt.*
 17     ,sum (d_to-d_from) over (partition by id,state,sub_state order by d_from) d
 18    from tt tt
 19  )
 20  group by id,state,sub_state,d_to-d
 21* order by 1,4
SQL> /

        ID STA SUB_ D_FROM   D_TO
---------- --- ---- -------- --------
         1 act std  01.01.16 01.02.16
         1 pas wait 01.02.16 01.03.16
         1 act std  01.03.16 01.05.16
         1 pas wait 01.05.16 01.06.16