Rezize Windows Partition does not effect the Mac OS partition.

First of all, sorry for my english, I am not a native speaker

So my problem where I did not found an answer in the Internet is the following:

I have a Macbook Air with 64GB Harddrive disk.

I have installed Paralles 8 and the virtual machine got half of the whole disk space. Now my OS disk is nearly full and I choose in the configurations of paralles to rezize the partition for the virtual machine. I have no advised just 14,2 GB for the Windows 7 partition but my disk space in the OS partition does not increase.

So anybody an idea what I can do?

Thanks in advance

Phil