Switch to a different cityfibre ISP - is it seamless?

Currently with Vodafone on a Cityfibre connection and will be out of contract in a few weeks. If I decide to switch to another (Cityfibre fed) ISP how seamless is the change? Would I need to inform Vodafone or would the gaining ISP do that?
Would the new ISP use the existing fibre and ONT?
I dont use my ISP DIgital voice line off the router as I have my own VOIP line.
Thanks.

It really depends on the ISP you are thinking of moving too.
The ONT remains the same as does the fibre. I moved from TalkTalk to AAISP, they have a straight forward process in place. Which meant the service was only down for around 20 minutes on the actual day of the switch.

The reality is that you could potentially be without service for an extended period of time as the official process is a cease and re-provide via the gaining ISP.

Thanks Gordon

Good Afternoon

Cityfibre are now moving to a gaining provider lead system (this was launched in the last few weeks) so you should actually find the move process is easier now

Good to see they've finally got the process sorted for moving.