SUBROUTINE KNCHNG(IT1, IT2, ITYP, LCOVAR)
C
C  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
C   Copies track IT1 into IT2, but changing the particle hypothesis to that
C   specified in the call. This routine is useful when a fit is done and
C   the, say, pi version of the track is updated and you also want to update
C   the K and p versions.
C
C  IT1     integer variable (read)
C          Input track number in KN list.
C
C  IT2     integer variable (read)
C          Output track number
C
C  ITYP    integer variable (read)
C          Particle hypothesis to use
C          1-5 ==> e/mu/pi/K/p
C
C  LCOVAR  LOGICAL variable (read)
C          TRUE  ==> recalculate track covariance matrix (energy related part)
C          FALSE ==> do not recalculate track covariance matrix
C  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>