Sql Server Saving changes is not permitted error Prevent saving changes that require table re-creation

Question

If I try to change a column type from int to real after creating and saving a table in SQL Server, I receive the following error:

Saving changes is not permitted. The change you have made requires the following table to be dropped and re-created. You have either made changes to a table that can't be recreated or enabled the option prevent saving changes that require the table to be re-created.

Why do I need to make the table again? I simply want to convert a smallint data type to real.

I haven't used the table until now, therefore it is empty.