Does anyone know the procedure or trick on how to remove the back cover of the side mirror, the big upper portion one? Somehow the one on my passenger side mirror has a crack and I plan to take it off, epoxy it, and put it back on, but I am afraid I will break the clips insidd the cover. Thanks a lot!

Thank you for the link! It seems the OP mainly talked about removing the mirror glass and the lower portion of the housing, not about removing the back cover, the red piece. I think only need to remove the back cover in my case.
[Added] Sorry I didn’t read the post in detail, OP did mention removing the back cover, there are screws holding it to the housing, looks like I have no choice but to remove the glass and those screws. Thanks again!