There is an issue with that concerning data loss as the DATA is a Blob in essence and we'll need that type in production.
In the spirit of attempts I tried to alter and received a:
feature not supported: ALTER TABLE ALTER not allowed to change datatype or length of TEXT/SHORTTEXT
However, I did create a test table with the DATA defined as a varchar and the SQL will execute returning information. Looks tied to potential changes in the execution of LIKE with regards to large (blob, etc.) data types.