The two patents that Huawei filed with the European Union Intellectual Property Office at the end of May — and were published last Friday — reveal one color scheme known as "Breathing Crystal" alongside a black/gray design. These color options might become available for other Huawei devices as well and should be unveiled in early September at IFA 2019.
https://www.notebookcheck.net/Dual-color-Huawei-P30-models-show-up-online-might-launch-at-IFA-2019.432733.0.html