Can I install SQL Server 2012 Express edition on a same machine with 2012 SQL Server Standard version
Suppose that as the Running SQL Server 2012 Standard SP1 instance name
  is ABC. Can I install the same instance name (ABC) of SQL Server 2012
  Express SP1 or it will be different.


You cannot have two named instances of SQL Server with the same name on the same pc. 

So your options are 


first uninstall your first instance and then install the second and
use the old name for newly installed second instance
give the second instance different name, but you can then alias it
with the first server's name once you uninstalled the first server


Here you can find information about aliases