There are at least two definitions of that expression:
1) "to wish away something" means to turn a blind eye on something, to forget it, to pretend as if you are not concerned by that and like everything is just fine , to ignore, to act as if it doesn't bother or harm you
2) "to wish something away" or "to wish away" sometimes means to detach oneself from reality and to fall into your own dreams, to dream a lot about something.
1) But you cannot WISH AWAY your illness when it is not convenient for you or for someone else. Inevitably, the headaches got worse, as did the fatigue. I started taking more and more sick leave. I am not a mind reader, but I got a distinct sense of my boss' disapproval every time I took time off.
2) Skin the sun
The soul is cheap (K. D. Cobain)
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If I could say what I want to see
I want to see you go down
On one knee
Marry me today
Yes, I'm wishing my life away
With these things I'll never say (A. Lavigne)