Nelly Moser maybe?

Nope, I seriously doubt it is Nelly. She is white/pale pink with a darker stripe.

One of the issues that impedes ID'ing a clematis cultivar just by photos is that colors do not necessarily photograph true and sun or shade will also affect the coloring. Looking at the two photos provided, it almost looks like flowers from two different vines - one a lavender-blue and the other a slightly washed out mauve.

Based on the first photo, I'd almost think it was Blue Ravine but the second photo looks nothing like that.

Definitely more in the mauve camp. Pretty sure not Blue Ravine as I’ve never purchased that one.

The top photo was taken at about 6 a.m. and the bottom was taken around 1 in the afternoon