...
In the Media Configuration, Publication Dates typically set the "From" and "Until" dates of a Campaign Item. However, if the "Manual Date Range" field is included in the Campaign Builder, custom date ranges can be set for the campaign item. This can be done by checking the manual date range checkbox on the Campaign Item.
...
Setup
...
Placement-Based Scheduling for Publication Dates
Information about Placement-Based Scheduling for Publication Dates introduced in version 2.167 can be found on this wiki page: https://advendio.atlassian.net/wiki/spaces/SO/pages/126775350/4.3.9+Publication+Dates#Placement-Based-Scheduling-for-Publication-Dates
Setup
To activate the availability mode, simply click the checkbox labelled "Enable Availability Mode Calendar" in the Item Configuration Settings “Enable Availability Mode Calendar“.