He has refused to cooperate or take responsibility.

@Chris Cooper , Ryan Dossey is correct.  

That requires their cooperation and assistance.

We need people to want to get into the business so they will buy memberships, attend meetings, buy our books, buy our cds, pay us to mentor them, be there to listen that we are offering everything free while all the time at every single opportunity let them know that if they want more, the real good stuff of course we have that too, at a price :)You need cooperation, you need collaboration, you need financing, you need partners, you need every advantage you can get.

They will usually allow 3% towards buyers closing costs, and pay regular real estate commissions with co-operating brokers involved.

He took out language that said I would cooperate with buyer's agent.

You'd both have to be on the same page and it would require the contractor's cooperation.

I  guess I’m going to have to ride this one out until lease is up or if she will cooperate at some point maybe I’ll let her stay.

And it's always nice when the old tenants cooperate with showings.

At this point, the tenant may have little incentive to pay you rent, pay for damages, cooperate, and/or leave the place clean and without further damage.