How to get a "partial release"

[Max T.]

I own two properties, both covered under the same mortgage, but both have unique tax ID numbers. I want to sell one of them but since they are under the same mortgage I have to get the lender to agree to a partial release. The guy seemed hopeful at first but I haven't heard from him in a few days. Note: the property I want to keep appraised for about 8% over the balance on the loan. How can I keep this moving along and what recourse do I have if they say no?