How to change the Callback function of a GUI button?

I would like to change the callback function associated with a GUI button dynamically in the programming way.

Here is the code piece I tried, but it does not seem to work:

const char* pstrLabelSaveJpeg = "SaveJpegCb";

SetCtrlAttribute(pahel_id, ctrl_id ,ATTR_LABEL_TEXT, pstrLabelSaveJpeg);

int CVICALLBACK SaveJpegCb(int panel, int control, int event, void *callbackData, int eventData1, int eventData2);