Expanding an existend volume

[Horni]

Hello to all,

I had entered more 150 GB to my Virtual Box in the configuration. Once in the box again, I must see, that between the volume to be expanded and the new space is antother volume. Unfortunately there is no possibility to delete this partition - the option are only "help" and no drop down menue.
How can I proceed to enlarge the existent partion of 50 GB to 200 GB?

Peter