As far as I know (Alberta Electrician, Edmonton Area) to safely change a panel, you need to de-energize the incoming feeders. To de-energize incoming feeders, you need power utility company to pull your meter. To get the power company to do this, you need an electrical work permit from the city. Almost all residential electrical work and permit pulling can be done by the home owner EXCEPT when working on the service. That requires a master electrician. After the work is complete, you call for inspection. Once inspection has passed, power utility company comes and reinstalls the meter.

The way Ive done it, we plan it. Get a permit. Get all the material. Epcor pulls meter at 8am, swap the panel, inspection, meter reinstalled by 4pm.

Long story short. You should hire an electrcial contractor to perform a panel swap.