Is it possible to modify the sql of a view on the fly?

I have a find form and I would like to give the option of searching based on:

SELECT Providers.iid, Providers.lname;
FROM rac!providers;
WHERE UPPER(Providers.lname) = UPPER(?vp_lname);
ORDER BY Providers.lname

or:

SELECT Providers.iid, Providers.lname;
FROM rac!providers;
WHERE UPPER(Providers.lname) Like UPPER(?vp_lname); && like instead of '='
ORDER BY Providers.lname

This means that they can search all providers whose names start with "rob" or all providers whose names CONTAIN the string "rob".

Or perhaps there are other ways to accomplish this?

Thanks!

Alex