Lock other user's operations when updating document

Hello,

I'm using DI API DoQuery to update package table. I'd like to lock other user's operations on  the current document such as modify address info, change value on some UDFs on Delivery header and detail tables during the package table updating.

I found StartTransaction/EndTransaction on DI API.It seems block all Delivery documents that I can't update others.

Am I wrong? or is there any other solution?

Thanks