Can University revoke my degree if I change some results, and how can I correct it?
This is very serious academic misconduct, of the type that reduces the confidence that the public and other scientists are able to have about scientific results. It doesn't matter if you did not change the raw data - you can't expect any readers to actually go through and do this analysis. Therefore, it is the results of the statistical tests, p-values, etc, that truly matter.

You should correct the problem as soon as possible, and beg for forgiveness. If this was done at the instruction of your advisor, that could be grounds for their dismissal from their position regardless of tenure. If you have submitted this work to any peer reviewed publication with these errors, you should inform the editors immediately and submit corrections that include the impacts on interpretation or withdraw the paper entirely.

Your program and your advisor have failed you in their duties if they have made completion of your graduate degree dependent on significant results. You should always design experiments that teach you something regardless of the outcome. Your institution should grant your degree as long as you have done sufficient work; this may be a lengthy, difficult process for you, particularly if you lose support of your advisor for this, but you may not want the support of your advisor if this turns out to be a pattern in their work. Most institutions have staff dedicated to academic misconduct that can assist you in this process.