The credit card details cannot be changed directly on the Ubigi Monthly Plan you benefit from, so you need to cancel it manually beforehand on your Ubigi account.
Once cancelled, you can subscribe to the same Ubigi Monthly Plan again (or another one) and enter your new (or other) credit card details during the subscription process.
NB: to avoid a double fee charged for the same period, ensure that you do the new subscription at the end of the current renewal period you benefit from (⊠and if it happens, you will benefit from a double data plan on that same period đ).