record.submitFields

 let id = record.submitFields({
                                type: record.Type.SALES_ORDER,
                                id: recordId.id,
                                values: {
                                custbody_jj_installation_required: hasAssemblyRequired
                                },
                                options: {
                                enableSourcing: false,
                                ignoreMandatoryFields : true
                                }
                                });