To modify the VIP address in tmsh via CLI

modify ltm virtual MF-80-VS destination 10.55.50.x:http

You may also copy out the LTM Configuration. That is much easier as well. That way we can respond with the correct syntax.

Also, something helpful to verify your config is this.

tmsh load sys config load verify partitions all

Then take verify out to make the change if it comes back clean.

I'm getting error -bash: modify: command not found