Shards without replica remain unassigend


I had an ES cluster with 3 Regular (Master + Data) nodes.
We have decided to split these into 3 Master and 3 Data nodes. Some of our indices does not have replicas being setup. When I shutdown one of the ES regular node and started 2 nodes, 1 Master and 1 Data node, the shards allocation did not happen. The shards which does not have replicas remained unassigned. How can I over come this and bring the unassigned shards into the cluster.


Does the data still live on the nodes under the relevant directories?