Well, I've never tried making that switch, I always cue-fed.
But it should be possible. For starters, every time she cries, offer nursing. And offer nursing both before and after meals of solids. Basically every time you think of it, offer it.
If she doesn't want to, that's fine. But the more you offer it the more different it will be from the previous schedule, and eventually she'll probably take it when she wants it.
Breastmilk has far more nutrients than most table foods. Don't worry about how much solids she's eating, she'll take what she needs. And finger foods are fine, just give her those. Purees actually aren't necessary at all for most children, even at 6 months.
So really, offer her parts of your meal when you eat, let her feed herself what she wants, and she'll be fine.
You may have to give up having the whole family on the same schedule. Some children will happily sleep later, others will not. You probably need to, as much as possible, respect her needs in this area. If she's going to be an early riser, you're going to need to have her in bed earlier too, you know?
Just offer before naptimes. You can't force a baby to nurse, and really, trying to force them is no more respectful of their needs than trying to refuse them.
Just offer the nursing lots and lots of times a day, and don't worry about it if she's not interested. Many children are pretty distractable around 12 months anyway, and might not nurse to sleep even if you *had* been nursing them to sleep before.
Just offer the nursing, and then put her down for the naps however is working for you (except if that's letting her cry, of course.) You may find you need to find an alternate way to get her to sleep. Those could include lying down with her, nursing her to sleep, singing her lullabies, patting her, walking up and down a dark hallway with her, wrapping her in a blanket and holding her until she falls asleep....