Modify Table-Valued Parameters
One option is to drop the type and then re-create it. You will have to modify all the modules that use it first, so a better and less disruptive option might be to create a new table type with the right data type, modify each of the modules to point at the new type, then drop the old one.

The syntax is simply:

DROP TYPE dbo.TableValue_Test;


However this will fail while modules still reference the type. If the TVP is only referenced in client code, you might have less to worry about, but you should still update the app code to use the right data type from end to end.