Hi PM70,
For K2 migration please refer to the below share KB article link.
https://help.k2.com/kb001356
However, I highly recommend that you reach out to your local K2 Services team for guidance and or hands on assistance regarding your query as the description differs a bit with scenarios explained in the above provided KB link.
To do this please open a request on the customer portal https://portal.k2.com/ticket/client/customerconsole.aspx
Should you not have credits to open the request, you can purchase some using the K2 store https://store.k2.com
You can also contact your K2 Account Manager with any further questions.
Best Regards,
Abraham.