CloudClient -- change lease / expiration

I’m using CloudClient 3.4 against vCAC 6.1.1

I have several machines I need to change the lease for.  I’ve worked my way up to figuring out that the command I need to run is:

vra provisioneditem action execute --id da813a6e-af7a-46b7-a528-36f092c40c8a --action "Change Lease" –properties “expires=MM/DD/YY”

When I run that command, I get:

CloudClient>vra provisioneditem action execute --id da813a6e-af7a-46b7-a528-36f092c40c8a --action "Change Lease" --properties "Expires=2/1/2016"

Error: The input provided resulted in a REST exception: Unknown field: Expires. The HTTP status is 400 - BAD_REQUEST.

I need help with what to put behind --properties.  What prop(s) drive(s) lease expiration?

1. What do I need to put in the properties field?  (Property name(s)?  Is there a certain date format?)
2. Can I pass multiple machine IDs via a single command?  I would assume that I would comma-separate them and wrap the whole thing in quotes?
3. Am I on the right track here?

Thanks!