Question: how to change vmfs5 to vmfs6?
Answer: Migrating from VMFS5 to VMFS6. VMFS 5 and VMFS 6 can coexist on the same ESXi but, of course, on different datastores. Due to the changes done in VMFS 6 metadata structures, there is no way to upgrade from VMFS5 to VMFS6. You need to build a new VMFS6 datastore and migrate the VMs to it.