I am having surgery on Thursday! Please help me.?

I am having shoulder on surgery soon and I just finished having a very very mild cold, I had Pre-Op today and everything went fine. i still have a little Phlegm but not bad at all. can this cause me to have to cancel? would this be a problem? I have no coughing or anything just every now and then it builds up in my chest and i spit it out please help. I dont want to have o cancel surgery :/