Altering primary key in database

Hi all ,

I have some tables in my DataBase ( Sql Anywhere 11 ) , which i want to modify a column from smallint to an Integer .

Usually i do that by letting the user runs ( or doing it auto as the application opens )

execute immediate command.

the problem is the column the primarykey in the table .

There is a way doing that in run time ?

( the application runs over 400 users , each one with his database )

Thanks

Moshe