Change SQLite columns type from INTEGER to BLOB in existing table with data

I use SQLite database (or sqlite3 class) in my software written in C++. In the new version of software I need to change data type on several columns in an existing table from INTEGER to BLOB.

Is there an easy way to do this programmatically?

Do I really need to recreate the table? The reason I hesitate to do so is because the table also has an index associated with it, and also is referenced by other tables attaching them to it.