Release dash during the shinespark wind-up animation to exit X-Mode, interrupting the shinespark and gaining a blue suit.
A blue suit will not be gained if dash is released after a shinespark has crashed against a wall or object.
Releasing dash mid shinespark will cause Samus to SuperJump and potentially go out of bounds but this can also be used to jump away from spikes or thorns.
Care must be taken around spikes or thorns after a blue suit is gained if there are active enemies as I-frames will expire quickly and escaping can be difficult.
See also: Tech Page