Sit alongside your child with them holding the book.
If they still need to point at text (up to about yellow 6), make sure it's them doing the pointing.
If they make a mistake, wait until they have finished the sentence or page - they may notice, go back and put it right themselves. If not, try saying "something was not quite right here - try it again", before telling them.
If they get stuck and ask you what a word says, try saying "what could you do to work it out?" or "what do you think?"
Sometimes you may just need to tell them to keep the flow of their reading, but given a little thinking time and a prompt to try themselves, they might just surprise you!