Best friends to cordial coworkers

The TLDR is I used to be best friends with someone, now I'm not. I still love her, but I've reached the final stage in post relationship grief, acceptance. We've apologised for what went wrong, but still haven't talked about it. As of right now she seems to have little interest in becoming closer, and I respect that. I also know we both still care about each other. We see each other all the time because we woek together and have mutual friends. There's no drama, and it's less tense than it used to be, but still awkward. Especially because I have feelings for her, and I think she used to have feelings for me. How do I show I'm still down to be friends again, if she ever changes her mind, while respecting her boundaries?