Sending a second reminder to a professor about LORs, after the first reminder

As graduate school application deadlines roll around this season, I believe this site would get a lot of questions concerning letters of recommendation, including sending reminder e-mails to professors about this.

My question is now what is the best approach to sending a second reminder to a professor concerning writing an LOR? A couple months ago, after having discussed my graduate school plans with the professor, they agreed to write his letter and have me send them the e-mail link to the LOR. I sent the first reminder last week, but they did not respond. And this professor is normally responsive in e-mails about other things, such as coursework and advising. I suspect the professor is beyond busy, and I hope that is the case; I just hope they forgot about the LOR or changed their mind about it.

I would like to add further that my two other recommenders have already submitted their LORs. I am still waiting on this professor now. Should I mention this in my second reminder e-mail to them, if I should send that second reminder at all? What should I be saying in the e-mail, to politely remind them for the second time?

Any input helps.