We need to replace some documents sub types in Windchill, How we can do this? Can anyone suggest us.
I think this posting (Re-Type a Document (change soft-type)?) will meet your requirements. If not, can you please provide more detail?
The methods mentioned seem very risky.
Home-grown utility seen in image below used here for many years successfully. It does essentially the same thing but avoids having to apply a command directly to the database via SQL We didn't develop it - got from a fellow Windchill admin.