Tailf extention not working

Hi everyone,
In one of the yang model, I was using below tailf_yang_extensions, with all the operations(create/merge/replace), it’s appending instead of removing first and adding new ?Could someone help me solving this issue ?
tailf:cli-reset-container
tailf:cli-remove-before-change
tailf:cli-delete-when-empty

Thanks
Srinivasa