No you cannot remove the events from a particular host to make space in the indexes.
Because the data is stored in buckets (lowest unit of storage based on the time) and you will have to delete the bucket to make space, this means potentially data from other hosts also stored in the same bucket.
You will have to wait for your time/size retention rules to kick in in order to make space, indistinctly of the host.
The partial alternative is to use the "|delete" command, that will hide the events, not save any disk space.
This would be related to the metadata still available for this host. When your
deleted data (buckets) gets frozen/deleted, this host will no longer be listed.
As @yannK wrote, you can manually delete buckets but this is potentially dangerous.