Disable prevent saving changes that require table re-creation.

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

Find Options under the Tool menu item in Microsoft SQL Managment Studio.

Uncheck the Prevent saving changes that require table re-creation in the Designers section under Table and Database Designers.