how to disconnect main service drop at service panel
If there is a main switch or fuse right under your meter you can operate those, if your connection lacks that features or those are 'locked' so only the utility can operate on them, you'll have to call SCE and ask them.

Edit: also check if your contract can hold 200A on 'meter side' if it doesn't and you load your panel for 200A SCE fuses will blow and you'll have to call for service restore, so ask SCE to check if your service is capable for 200A

EDIT2:
I post my meter and panel as example:
You can see on my meter the bundled main disconnect, see if there is one on your too. On my panel you can see the main GFCI breaker (right) and the circuits' breakers, so I can remove power both from my main switch and from the meter itself. Here on older installations, now replaced, where main disconnect were fuses.