How to handle fields dependencies in Formik

Hello,
I followed the example in the video #9 under the Forms Lecture of the React Native course:

After extracting the Form component I have a structure like this:

<Form
	initialValues={{
	  fieldA: "",
	  fieldB: "",
	}}
	onSubmit={handleSubmit}
	validationSchema={validationSchema}>
	<FormTextInput
		name="fieldA"
		placeholder="Field A"
		required
	/>
	<FormTextInput
		name="fieldB"
		placeholder="Field B"
		required
	/>
	<SubmitButton>Send</SubmitButton>
</Form>

In a scenario like this, I would like the text in fieldB to be cleared when the text in fieldA is cleared manually.
In this set up I don’t have access to formik methods like setFieldValue etc.

How can I detect one field changing (ok i could create an onChange event), and especially how do I edit the value of another field?

Just use onChange(yourHandlerFunction) on your input! Check docs here