I don't believe PI allows you to change the port 9991 used by the server to listen for Netflow records. It may be possible if you hack into the daemon settings in the underlying shell but it would not be supported.
Note you need the Assurance license to use the Netflow features.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...