Unable to Modify User-Defined Table Type

I have a SQL User-Defined Table Type. It used in more than fifty stored procedures.Now i need to change a column in that table type. I tried to drop and recreate the User-Defined Table Type.But SQL Server doesn't Allow that. It shows up following error.

Msg 3732, Level 16, State 1, Line 3
Cannot drop type 'dbo.UserDefinedTableType' because it is being referenced by object 'SP_DoSomething'. There may be other objects that reference this type.
Msg 219, Level 16, State 1, Line 3
The type 'dbo.UserDefinedTableType' already exists, or you do not have permission to create it.

How to alter the User-Defined Table Type without modifying all the Stored procedure that uses User-Defined Table Type ?