Just say "Hey Cortana, open Alexa" to a compatible Windows 10 PC or "Alexa, open Cortana" on an Echo device to get things going. Microsoft set up a web page where interested developers could receive notifications about the integration at the Build conference in May, and now, finally a preview of the setup is available to all.
Last year, Microsoft and Amazon announced the two companies would work together to integrate their respective digital assistants. Although Cortana has been available on Windows 10 devices since 2015, Amazon Echos had been on the market for almost three years before the Harmon Kardon speaker with Cortana was released last fall. If you're on a Windows 10 PC or have Harman-Kardon Invoke speakers, try "Hey Cortana, open Alexa" or click the microphone button and say "open Alexa". This means you can call Alexa on Cortana and vice-versa. Those who take part in the public preview will be able to share feedback to improve the experience, both companies said today. You can now access both Alexa and Cortana on each of them.
The Verge reports that Microsoft and Amazon have released a wider public preview of its previously teased deeper integration between the Alexa and Cortana digital assistants - available for everyone in the United States right now.
In today's announcement Microsoft bravely suggests that just as users need different people to service cars or offer financial advice, they could use two different digital assistants to manage work and home, while also needing them to collaborate.
Again, this is a preview version of the Alexa/Cortana integraion so not everything works, e.g. you cant ask Alexa to play an audiobook through Cortana. Features such as music streaming and alarms will be added later and eventually it's hoped that the syntax can be worked out so there isn't a constant "he said - she said". Microsoft tells us that "many" of those skills will be available at launch, with more coming later down the line. As for Alexa users, Microsoft says Cortana's knowledge, as well as calendar management and rich email integration, will come in handy for Alexa users.