How to replace ntext with nvarchar(MAX)?

I need a column that can hold large texts in Unicode. The ntext data type is deprecated so I have to use nvarchar instead. The current column is of data type text so I tried to change it like this:

alter table tableName change currentColumn newColumn nvarchar(MAX);

This doesn't work. When I replace MAX with numbers it works but I don't know what is the maximum number I can replace it with. I am going to store really large texts.
How can I make this work?

 

Which version of SQLServer are you using?

 

I found a good description that will probably answer your question:

Source: teratrax.com

So if your not using SQLServer2005, it is probably the problem.