For those interested in changing your child's instructional model, the window will reopen in HAC from September 28-October 4. The new grading period begins for elementary students on November 9.

From CFISD (https://www.cfisd.net/en/lead-safely-2020-21):

If you would like to make a change to the learning option for your child(ren) for the 2^nd grading period—from CFISD Connect to On-Campus or from On-Campus to CFISD Connect— the selection window will be open between Monday, Sept. 28 and Sunday, Oct. 4.  This change will be effective beginning Oct. 19 for middle and high school students and Nov. 9 for elementary students. A follow-up letter will be sent on Monday, Sept. 28 with instructions on how to make the change. If your child is continuing with the same learning option for the 2^nd grading period, no action is required.