Blue over pink?

Depending on the strength of the blue it will either be blue or lilac. The more pigmented the blue, the more blue the result.

It should fade lilac rather than green. Although I would suggest that you use a purple based blue not a green based one.

why dont u wait for a few days or weeks until the pink part is gone ? must safer that way  ;D

What shade of blue is it?

If you used something like Live XXL Pink then bleaching it takes the pink out almost instantly which means not having to leave it on for long, then you have a blonde base to put the blue on (This is what I did and it worked). Hope this helps.

That's isn't something you can guarantee. Even if it was the same dye that was used, it is still someone else's hair and it can behave very differently. Bleaching colour our is generally a bad idea as it can drive the colour in deeper.

Many pinks turn neon, bright highlighter pink, when bleach touches them. There are many more predictable and much safer ways to remove direct dyes.

I have covered faded out pink and lavender with blue and it covered just fine. It was a very pigmented blue conditioner that I used. Do a strand test to see what would happen. If the result doesn't come out as bright as you would like, then fade further or you might need a more pigmented blue.

Thank you for all your anwers! I'm not dying it blue yet, but I'm considering it, maybe a few months from now. I love lavender as well, so I was wondering if dying it blue would make it stay blue and then wash out to lavender rather than green. I know it depends on what color the dye is based on, but I already have an idea of what it will be like. Thanks!  *hugs*

A pink base is ideal for preventing a green fade from blues