Azure + Terraform state file is out of SYNC

Hi I am having issues with running terraform on existing resource group. I did some manual changes in state file as well as deleted existing resources from resource group to fix the deployment issue of AKS cluster. i dleted the cluster manually and removed the cluster module from state file . it did installed the new cluster but previous cluster is still occupying the route table and hence cluster is always in failed state. Please let me know what is best solution to import existing state and get the code woking. Thanks