Workflow creation

Dear experts,

I have a program with 1000 lines of code, which updates 2 data base tables, at line 600 it updates the first table and at line 950 it updates the 2nd table. (it is working correctly today)

So, now my requirement is to generate a workflow once the 1st table is updated and send the workflow to the user and only when the user processes the work flow the system should execute the rest of the code(from line 601) and update the 2nd database table.

Can someone please direct me on how to do this.

Thanks for your time

-Amit