Since 1 January 2018, Section 650b of the Civil Code has regulated how the client of a construction contract can change the work. First, the two parties try to agree on the change and on the extra or reduced payment. The contractor must make an offer. For a change to the agreed result, this applies only if carrying out the change is reasonable for the contractor. If the client is responsible for the planning, the contractor must make the offer only after the client has done the planning for the change and handed it over. If the parties do not agree within 30 days, the client may order the change in text form.