Shimano right crank arm O-ring

Hi, folks. I’m refreshing a new-to-me M7000 crankset. It’s in great shape; I’m just tidying it up before installation.

How would I go about removing the (flattened) O ring around the base of the right crank axle? (Yellow arrow in pic)

More importantly, how hard would it be to install a new O-ring? (Red arrow)

There definitely isn’t as much room to maneuver as on the left crank arm, where the O-ring pops off easily.

Thanks in advance!