Here you will find an example of how to convert a model from a frozen tensorflow model by using WinMLTools. To get possible output names of a tensorflow model, you can use summarize_graph tool
WinMLTools enables you to convert ML models created with different training frameworks into ONNX. It is extension of ONNXMLTools and TF2ONNX to convert models to ONNX for use with Windows ML.
filename = 'frozen-model.pb'
output_names = ['output:0']
graph_def = graph_pb2.GraphDef()
with open(filename, 'rb') as file:
g = tf.import_graph_def(graph_def, name='')
with tf.Session(graph=g) as sess:
converted_model = winmltools.convert_tensorflow(sess.graph, 7, output_names=['output:0'])