Hair advice, will they be able to highlight on top of all the box dye?

[LipstickLoves]

Just as the title says, I've got an appointment with a new hairdresser this weekend. I'm 40, have quite a bit of grey coming in.

I've been box dying my hair brunette but it feels like it's loaded with colour, dark and patchy.

I've booked a full head of highlights for the weekend, it's a last minute booking, I'm
an NHS worker and can't fit in a consultation before my appointment.

Anyway, my question is, will they be able to sort it???

How much lighter are you wanting to go? And how dark is your hair just now?

Surely they'd need to do a patch test on a new client before they dye it?

I've had highlights with a box colour on, they said they can only use one colour though whereas I would normally have a couple of different ones.