Please complete the GLA House Plan Modification Request Form for more information. After a Study Set is purchased GLA will provide a one-hour initial consultation to discuss your desired modifications. After the consultation we will provide a written estimate to bring you closer to the perfect plan. Proof of purchase is required for plan modifications. An average up to 3 weeks for common plan modifications. Depending on the complexity of the changes and our schedule, it may take longer. Clients will need to accept quotes and pay a deposit before completion.