Taking the loss now is preferable to paying out monthly for the privilege of being a landlord.

If I move to a partnership, what happens to my accumulated passive losses? 

Sell at a slight loss.

If indeed a loss is taken on this which it sounds like is a fair possibility then if the agent was representing you the agents E and O will/could kick in and that's where you might get some financial relief.

You will have to gather more accurate operating costs (vacancy loss, taxes, utilities, insurance, mgmt fees, maintenance, HOA) to best determine potential future performance.

It may be time to cut your losses and move on from this real estate. 

It's ok to sell properties at a loss (you get the downpayment back to repurpose into something better).If you have four or more properties, this is what I would do (I just posted part of this as an answer to someone and thought it would make a good post):1.

Quote from @Christian Pichardo: Quote from @Caleb Brown: Should you cut your losses and move on?

I do this at least quarterly for some of my clients and they like being able to see the profit and loss reports. 

If I had to pay my cleaners on top of the loss income it would impact even more as my cleaning fees range from $100 to $400 depending on the property.