thanks all !!!
using sp_rename just right solution for me!!
the reason i want to change column name is, i couldn't set off Identity Property.
so i need to do these:
1.create a temp column
2.set values = identity column
3. drop identity column
4.set temp column name to the identity column name
i think is better than what EM does--create a temp table, copy data to temp table, drop original table, rename temp table name to original table.
also i dont know how does EM generate table script, include all column property , indexes and trigger...ect.