You can contact licensing to see if they are able to do this. They will need to provide you new licenses broken up as described though, there is no way to do this on your own as far as I am aware.
Through the support portal you can just create a new ticket and set the 'product' as License Management. I think that would be the best way to go about this.
I took the same route James had mentioned. Having to shuffle around licenses can be rough. You can try requesting for permission to cut your own temporary licenses to fill in any downtime if it is a day to day request.