Cancelling

verb

1. To cross out something with lines etc.
2. To invalidate or annul something.

   "He cancelled his order on their website."

3. To mark something (such as a used postage stamp) so that it can't be reused.

   "This machine cancels the letters that have a valid zip code."

4. To offset or equalize something.

   "The corrective feedback mechanism cancels out the noise."

5. To remove a common factor from both the numerator and denominator of a fraction, or from both sides of an equation.