Amends to architectural drawing

We are getting a loft conversion - and worked with a design / architects company to get plans drawn up to meet planning conservation regulations (which we got approved)

We are now moving to the build stage - however noticed the internal staircase on the plans is in an awkward position and our builder thinks this can be amended - however we need the architectural drawings up dated so we can submit to building control for pre-approval

Is this something you can help with (if we send over the various files)

Let me know if this makes sense | if I can provide further info

Jim