Once you moved you should have alerted the MN employer and they should have automatically stopped the MN withholding ... if not tell them to do so and fill in whatever withholding form MN has if needed. The W-4 is for the federal return and doesn't need to be changed since you still have to pay federal taxes even if you live in FL.
Submit Minnesota Form W-4MN to your employer. Check Box B in Section 2 to claim exemption from MN withholding. Here's a link to the form: