Minor changes to dwg file to complete house planning drawings

I need someone who is well experienced with house planning drawings to make some minor changes to a dwg file. The building design does not need to change, just an update to the base level so the planning drawings align with an engineer's site and drainage plan. The elevations will also need to be amended slightly to show a slight increase in the height of the walls. For an experienced plan drawer, the task should not take about an hour.