I'm still a newbie when it comes to status

I'm silver and 48 hours to check in

United bumped me to E+ which I'm happy about - and selected a seat for me - but there's an available seat closer to the front of the aircraft that I'd prefer as I have a tight connection

Looks like I'd be charged for the seat despite already being in E+

Any tips on how to acquire this seat, gratis, before T-24?