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This is precisely the reason floating IPs that NAT to other IPs exists
(not, as we think, to provide public IP access... we can do that with
fixed IPs).

Moving ports, moving the IP, they all involve a few layers of cache
invalidation and complex manipulation at the lower networking layers. But
changing a NAT destination is relatively instant.

I'd recommend you using a floating IP for this. If you can't, please
explain.

Excerpts from Volodymyr Litovka's message of 2017-08-23 16:58:32 +0300:
> Hi colleagues,
> 
> imagine, somebody (e.g. me :-) ) needs to transfer IP address between 
> two ports. The straight way is: release IP address and then assign it to 
> another port.
> 
> The possible problem with this way is time between release and 
> assignment - during this time, this IP address is in DHCP pool and can 
> be automatically assigned to some another port upon request.
> 
> Any ideas how to prevent leasing this IP address during this time?
> 
> Thank you.
>