Hi j_odie100,
You will need to disconnect and re-connect the existing MTD connection within the product. To do this, go to Taxes > Edit VAT > Edit settings > Turn of via the MTD switch.
Once turned off here, go to the Cog Wheel > Accounts and Settings > Advanced > Making Tax Digital > Learn how to disconnect and follow the in-priduct messaging to complete the disconnection.
You can then go to Taxes to turn on the connection again, and will be re-directed to enter your government gateway details.
Thanks