Can I withdraw a paper from IEEE conference after signing the copyright form? I have submitted a manuscript using figures from google. I have cited the web pages from where I have found the figures in my article. The figures are actually figures of apparatus. Later I learnt from IEEE website that IEEE discourages usage of figures from web pages without prior permission which I have not taken. But I have submitted the paper and copyright form to IEEE conference. As the date for camera ready and pdfxpress is already over I can't edit my manuscript now as told by the conference chair.

What should I do now? How may I withdraw it from here and publish it in other place? Is it possible to withdraw after signing copyright? Is it worth requesting the conference chair to open the pdfxress for few minutes so that I may upload my new manuscript there? Please help me.
Email the programme chair and ask them how they would like you to proceed.  It is possible that they will still allow you to make changes to the paper, even at a late stage (provided it doesn't substantially affect the content).  If nothing else, they can ask the IEEE for advice, this is unlikely to be the first time this has happened, so there may be a standard answer already.