Can you add white to an already exsisting purple/black tattoo to lighten parts?

[kvaz]

I really just want to know if this can be an option, and how I find an artist who can do this. I've seen other forums where artists say they've done it and it worked out really well. I just don't know how to go about finding someone or even if it's a possibility. Help!

[SStu]

this depends on what you want to end up with.

Here is an example from Nathan Mould: