Calculating absence period triggers in 6 & 12 rolling months

Hi, welcome to teh forum

Always better if you upload a sample WB, but probably contain something like...
=EDATE(today(),-6)

To attach a file to your post,
click advanced (next to quick post),
scroll down until you see "manage file",
click that and select "add files" (top right corner).
click "select files" find your file, click "open" click "upload" click 'done" bottom right. click "submit reply"

Once the upload is completed the file name will appear below the input boxes in this window.
You can then close the window to return to the new post screen.

Based on the file, the following proposal may help.
1) Select cell E2 and paste the following in the formula bar then copy down: =COUNTIFS(A$2:A2,">="&EDATE(A2,-6))>=3
2) Select cell F2 and paste the following in the formula bar then copy down: =SUMIFS(C$2:C2,A$2:A2,">="&EDATE(A2,-12))>=6
3) Select range E2:F5
4) Select conditional formatting
5) Select 'Format only cells that contain'
6) Cell Value
7) Equal to
8) TRUE
9) Set fill to red (or apply the formatting that you choose)
Let us know if you have any questions.

Administrative Note:

Hello CANN15 and Welcome to Excel Forum.

We are happy to help, however whilst you feel your request is similar to this thread, experience has shown that things soon get confusing when answers refer to particular cells/ranges/sheets which are unique to your post and not relevant to the original.

Please see Forum Rule #4 about hijacking and start a new thread for your query.

If you are not familiar with how to start a new thread see the FAQ: How to start a new thread

Let us know if you have any questions.