You can recalibrate the esc by just repeating what you did you calibrate in the first place. Hold at w.o.t on tx and turn on the esc, that will put it back into calibration mode. If you are using a 2.4ghz radio system you may have to adjust the esc arm time to a greater delay as the esc may arm before the radio system binds itself. Use the castle link to do that.

Good luck