To do this, break the period into two parts.
The first - to the excluded time, the second - after.
Let's say we have such a repetition every day:
For example, we need to exclude all of August from the repetition.
Then go to the settings for repeating our period.
Set the Repeat till field on July 31.
Now create a new period from September 1 with a daily repetition.
The following periods are obtained:
Thus, we excluded time from the repeating period.