I need to mash the range of dates that cross over in SAS.

For example:

ID PROV dt_entrata dt_uscita FLAG
381 00001 31/12/2004 09/11/2005 OK
381 00001 05/07/2011 16/04/2012 OK
381 00001 31/12/2013 20/10/2014 KO
381 00001 19/10/2014 15/02/2018 KO

It must become:

ID PROV dt_entrata dt_uscita FLAG
381 00001 31/12/2004 09/11/2005 OK
381 00001 05/07/2011 16/04/2012 OK
381 00001 31/12/2013 15/02/2018 OK