Simple have Hitler get assassinated before 1939 and get someone more interested in maintaining economic stability as fuhrer.
forever .. war was not inventible in 35With a 1935 POD.
Britain and France start the process of serious rearmament earlier - say the various treasuries loosen the purse strings earlier - even an 18 month head start should make vast changes
For example the British Defence Spending at the beginning of 39 was just 4% (later increasing to 8%) of the Budget - increase this by just a few % in 1936/7 and that would pay massive dividends in 1940
The army may start to expand earlier - tanks and Aircraft production / factories expanded earlier as well as the associated technologies and their supporting industries.
For France - in June 1940 they were just on the cusp of completely modernising their Airforce (along with large numbers of US Built aircraft due to arrive) and their Tank Production was 2nd only to the USSR with the latest designs far in advance of the best German tanks of the day.