Voiding multiple items in a Sales Order

Hi, we're using 2007.

When I need to close multiple item lines in a Sales Order, I'll need to do this:

1. For each line to be deleted:
   1. Call GetByKey()
   2. Call SetCurrentLine()
   3. set LineStatus = bost_Close
   4. Call Update()

So I just want to confirm if this is the only way to do it? (if I don't call Update() in the loop, it will error out)

And secondly, do I need to call GetByKey() in the loop? Or I can do it first before entering the loop?

Please advise.

Thanks.