>>>I've looked at Help on ALTER TABLE and I don't see if it requires exclusive access or not.
>>
>>Yes it is
>>
>
>Is there any other way to change the structure of the existing table?
Nope, you are changing the table structure :-) not a value of the field.
Against Stupidity the Gods themselves Contend in Vain - Johann Christoph Friedrich von Schiller
The only thing normal about database guys is their tables.