@chris If you are already on XGS pon, then it is just a change in your profile and a few seconds of resync. If you're on Gpon , then they need to change your ONT/router (technically only a small component in it, the SFP needs changed). And at a position not far from your house, disconnect the fibre strand to your house from a optical splitter that leads to old GPON card in central office and connect it to a splitter that goes to a XGS pon card at the CO. fairly simple operation.

@jfmezei ya it should not be too much.
They'll be upgrading both the fibre terminal at the house as it is only 1Gbs as well as install their own router which I might not use but they are also installing their wifi APs around the house so it'll be a couple hours I imagine

@chris make sure the SFP in the new router they install and which you don't want to use can be removed and placed in your current router (or media converter). I woudl not accept their WiFi access point, Likely be locked to their own remote management only and tied to the router they install. PhotoL typical SFP module.