Formatting an exFAT partition to HFS+

I have a 2 TB external HDD with data on it. I partitioned the drive on Windows with half the drive containing data and is formatted to NTFS. The other drive is formatted to exFAT in Windows because disk utility in OSX does not recognize an NTFS partition. The partition map is Master Boot Record. I openend disk utility in OSX and tried to erase the partition to Mac OSX journaled but i get "Couldn't modify partition map. Operation Failed". I just want to format the empty partition to HFS+ without touching the NTFS partition with data on it. Can anyone help me out.

Thanks