Merge multiple state files into single

Hi, I have a terraform source code for creating a GKE cluster and two node pools from a single file (
Once cluster is created, we have a requirement to add new node pool from another file ( What is happening is we are getting two state files.

  1. state file with cluster and original nodepool details
  2. state file with additional nodepool
    I want third nodepool details to be present in first state file. Is there a way to merge two state files or to add 2nd state file to first one. We are using terraform workspaces for this.