SQL will not allow you to change the data type in SSMS using Design mode of a Table - you will get the message as above.
You can change the datatype using TRANSACT though - specifically using Alter Table, Alter Column.
For instance, the following does work without loss of data and without dropping and recreating the table;
CREATE TABLE [dbo].[VToNVTest]
(
[RecordId] INT IDENTITY(1,1) NOT NULL,
[DemoText] VARCHAR(50) NULL,
CONSTRAINT [PK_VToNVTest] PRIMARY KEY CLUSTERED
(
[RecordId] ASC
)
WITH
(
PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF,
IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON
) ON [PRIMARY]
) ON [PRIMARY]
GO
INSERT INTO [dbo].[VToNVTest]
([DemoText])
VALUES
('Test A'), ('Test B')
GO
SELECT * FROM [VToNVTest]
ALTER TABLE [dbo].[VToNVTest]
ALTER COLUMN [DemoText] NVARCHAR(50)
GO
SELECT * FROM [VToNVTest]
For Crystal to display the data correctly you will need to change the column type & set the font correctly & you may need to change the collation of the database
Kind Regards