Shimano Alivio Adjustment

[Retired in GA]

I purchased a new Trek Verve+ 3 ebike. The shifter works perfectly when shifting to a higher gear but does not downshift properly. When I select a lower gear I have to pedal for 30 seconds to a minute before the bike will suddenly downshift on its own. As I am a 2.5 hour drive from the dealer I would like to attempt to adjust the shifter myself if at all possible as I am somewhat mechanically inclined. Can someone provide a link or instruction as to how to accomplish this adjustment? I've emailed the dealer and will probably hear from them later today but meanwhile, if someone can provide some assistance on this forum that might help me get the problem resolved sooner, rather than later. Thanks in advance for any/all help.

 

[Art Deco]

Hello, I'll reply just to keep the thread going until someone knowledgeable shows up. Many videos available, Check Park Tools videos on YouTube.