  The crystal symmetry plays a pivotal role in protecting the nontrivial
electronic states in a topological phase. Manipulation of the crystal symmetry
and hence the nontrivial topological states would serve as a fertile ground to
explore exotic topological properties. Combining experimental and theoretical
investigations, we demonstrate herein the flexible switch of nontrivial
topological states in the single phase of kagome magnet GdMn6Ge6. The intrinsic
anomalous Hall effect caused by distinct Berry curvatures along different
crystallographic directions is realized through selectively breaking the mirror
symmetries in these directions by external magnetic field, which is fully
supported by the first-principles calculations. Our results set an explicit
example demonstrating the strong correlation between structure symmetry and
nontrivial topological states, as well as the switchable topological properties
in a single magnetic topological phase.
