I'm 39 and my hair is naturally very dark brown, and I have cool toned Caucasian skin. I have a few small greys appearing at the temples which I have been covering up, but no greys elsewhere yet. Recently I have felt my hair has gotten darker- for some reason- and the dyeing of the temples (using root touch up) has exacerbated this. I feel that with my face the very dark is now too ageing. Also the greys stand out like a sore thumb against the very dark brown, so I'm thinking a generally lighter level of brown would be better and easier to blend the greys as they come. I would ideally like a more ashy cool toned brown to help my skin tone appear warmer, rather than a reddish brown.
Please can a stylist advise me on how I could get my hair to lighten a level or so, from dark to a dark/medium cool brown? I have attached two photos here. The dark one is my actual hair today and the lighter one is what I'd ideally like.
Can this be achieved without serious damage? If so how? 
For background, over the years I have damaged my hair using bleach, colouring, straightening etc and over the past 2 years I've been trying to grow it and keep it healthy with no bleach. I have also had Brazilian knots to give me some length while I wait for it to grow.
Thank you!!