Are their any applications (any) that allow restructuring (changing
the type, size or existence) of an existing column within an SQL table
without losing any of the existing data?

Failing that, what is the best way programmatically, of going about
doing the same procedure?

Any ideas are truly welcome.

If you want to do it programmatically, then retrieve the original
table's structure (FieldDefs and IndexDefs of the table), create a new
table with the new structure, and batchmove the contents from the old
into the new table.