Modifying database

[RBTools]

I am using:
    RB 4.5.1
    Valentina V4RB 1.9.6
    Mac OSX 10.2.6

I need to modify the structure of my database to allow for a new table and
additional columns in an existing table.  Can this be done without having to
repopulate the database?  My thought was to use Vapp to modify the database
and then make the same changes in my code to match.

Any direction would be great,

Steve