A respirator for supplying a patient with breathing is provided such that the respiration will not be compromised at the time of a changeover from one form of respiration to another form of respiration. Provisions are made for carrying out a first form of respiration with the corresponding first setting parameters and for taking over the corresponding setting parameters at least partially from the measured values determined during the first form of respiration and the first respiration parameters that remained invariant at the time of the changeover of the forms of respiration at the time of a changeover to a second form of respiration.