Zephyr Single project Cloud to Cloud Migration

Hi

Can anyone tell me the best way to migrate Test Executions from one Jira Cloud Instance to another.  I can easily use the Jira importer to create new test and test steps but there doesn't seem to be any way to move the Test Cycles and Test Executions. 

Since we have 100s of tests and test steps in the old project, we'd rather not have to do this manually.