weaning

Neither. You wait until 6 months unless advised otherwise by a nutritionist/specialist.

In the UK, the guidance is 6 months, steady neck control, able to sit with minimal support, loss of tongue thrust, ability to put hands to mouth unaided and interest in foods.

You can wean from 4 months if your baby is fully ready and showing all the signs that they are just because Guidance is 6 months doesn't mean you have to stick to it

We have started weaning at 4 months and I just let us GP know but at the end of the day, it is your decision as a parent if your baby is ready . We are also weaning because my LO is sick all the time with milk but seems to be able to hold solids down with no issue

I started at 4 months, my baby was showing interest in food, we didn’t offer it every day, just here and there to start off with, things like mashed banana or avocado, he’s now 6 months and has so much more, we’ve just started to introduce small amounts of water here and there

Why are you wanting to wean?
I wouldn't be asking for permission, but I would speak to a HV for guidance on what and how to start.
Early weaning on an under developed digestive system can cause life long issues so I'd get tonnes of advice beforehand.