Change Public IP on FG 60C VPN Beste practice

Hi Guys,

we have 2 sites one in belgium with a FG100D and Fortimanager

And one in UK conected with ipsec site to site.

The public ip in UK needs to be changed.

So this is what i thought to do.

When im in the UK i will change the ipsec IP to UK in the Belgium Firewall.

I will then logon local on th UK FW and change the WAN ip to the new one.

From then on the VPN should come up or am i wrong ?

I will then import the setting from the UK FW into Fortimanager.

Is this a good approach ?

Thanks