With VMware, it's possible to increase the disk size, but unfortunately the VMware increase utility does not know about how to increase the actual BSD partition.
There has been some problems with this method and instead of trying to expand the disk, it is recommended to add a separate disk instead of expanding the existing disk. Please follow this guide on how to adding disk space.
If you absolutely have to, there is a guide here: how to increase disk size in vmware. Please make a VMware snapshot before you begin and if it doesn't work, please add a disk instead.