On the last step of the property analysis set up, Costs & Credits, Base Rent can be abated as needed.

In the above scenario, 100% of the first 3 months of base rent are abated from the tenant's lease payments.

Sometimes, abatement is not that straightforward. What if a 5 year lease has the first month of each year of the lease abated by 1/2, or 50%. In this situation, you would enter the following:

Using the "+ add another" button, the first month of every year of a 5 year lease (months 1, 13, 25, 37, 49) is abated by 50%.