Since applications live on a web server and there may be multiple applications on servers, it is not possible to transfer a single application without transferring the entire cluster and its servers to another account.

It is possible to transfer ownership of a cluster to another account which will include all the applications on the servers in that cluster.

You can transfer the Cluster(s) under the Settings tab. You can find this setting by clicking on "Servers" in the top level menu to see a list of your Clusters, then select the Cluster(s) you would like to transfer.

On the next page you will see the Overview for your Cluster, click on the Settings option in the sidebar and you will see the following:

Select the "Transfer" option and enter the new recipients email address. They will receive an email with a link to accept the transfer and then they can choose the account they want to assign it to.