What is the start date of my revision?

Per ASC 842 Glossary, the Effective Date of the Modification is the date that the modification is approved by both the lessee and the lessor. 
(Leases, Topic 842, page 23)

The effective date of the change to your lease may not be the date printed in the updated contract. 

When adding the Revision to LeaseCrunch software, the start date of the revision is the effective date, as described above.

If the Revision Start Date occurs prior to the end date of the original or previous lease, it may be necessary to add lease payments and other information from the previous lease agreement. 

For more about how to add a revision, click here.