How exhausting!
There's a section in one of the BW books where Tracy describes how to teach LO to get back down from standing. Along the lines of taking her hands (once she has stood in the cot) and putting them on the cot bars (rather than the top of the cot) then lowering her hands gradually down the bars until eventually her bum plop down on the mattress. She mentioned that LOs who learn to stand haven't yet learned how to get down again so they stay up until they fall...but then get up again.
You may also be able to help her learn how to get from the sitting position to the laying position in a similar way, rather than you repositioning or laying her down, you show her how to do it by bringing her hands down and forward on the mattress (or on the floor if it's A time).
I don't remember this being a long lasting phase for my DS but I do remember I had to break down the instruction into steps. If I said to him (once he stood up in his cot) "lie down" he ignored me (I assume he had no idea how to get to laying down from standing up). If I said "sit down" he would (or I'd help him down), then "lie down" (or help him lie down) and finally "it's night time, go to sleep." I also remember a more instruction tone (teacher voice) helped DS to know I meant it rather than trying to "sooth" him to sleep it was more an instruction that he must.
It will pass of course
One other thing to bare in mind, she is really young, floor time and crawling are far more important for her development in so many ways. I'm sure you can't just stop her pulling up to standing but personally I would not encourage it or offer help or a hand to hold to reduce the amount of time she spends up on her feet and more time sitting, tummy, crawling, rolling.
