If you're only changing the 2-fold axis along c to a 2-fold screw axis, you don't need to go back to the raw image files and reprocess them! Just tweak the header of the .sca file and carry on (and take notes on what you did).
________________________________ From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Vikrant Upadhyay [vikrant192...@gmail.com] Sent: Wednesday, November 06, 2013 5:13 PM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] switching space group Hi Maggie, you can re-process your data using XDS and can provide the desired space group in the XDS.INP file. It won't take much time. Vikrant Vikrant Upadhyay Postdoctoral associate Dr. Crina Nimigean's lab, A-1050 Department of Anesthesiology Weill Cornell Medical College 525 East 68th Street New York, NY 10065 On Nov 6, 2013, at 1:13 PM, MAGGIE <dongmeij...@gmail.com<mailto:dongmeij...@gmail.com>> wrote: Hi, I have a structure which should have space group P212121, but it has been processed to P21212. It can not be solved and refined. Right now I do not have HKL2000, but I need change the space group to P212121. Is there a way for me to do this using CCP4? Thank you, Maggie