Situation with MOH

So my sister is my MOH, right now atleast. As you guys might already know, her and I have had some problems. She is upset because of some scheduling issues with my shower and since then has not spoken to me.

i've tried to reach her by calling, e-mail and even facebook yet she ignores my atempts. Honestly, I am so sick of this crap I don't know wether to just plain ask her if she wants out of the wedding party or what??

Usually, I have a pretty hot head when it comes to things but since this is my sister I am trying to think before doing anything that would potentially ruin our relationship..well what is left of it..

Need some advice here...

at this point yeah, i'd just plain ask her. maybe that's what she's waiting for???