Hyper-V replicas - lack of space

Hi,

I have a Hyper-V Server (H1) that replicates to another Hyperv Server (H2).
Having setup replication so that there are 20 recovery points, it turns out
there is not enough space on H2 to hold 20 recovery points. In this situation,
if I reduce the number of replication points to 10, will the space on H2 become
avaialbe automaticaly as HyperV moves to use 10 recovery points over the next
day or so or do I have to clear out the old unwanted replica data on H2 manually?
And if so what do I have to delete and what is the safe way to delete it?

Thanks