What happens when you changing the Burden schedule an an Existing Award

Summary:

We'd would like to know if we change the Burden Schedule in an Award what would happen?  Would it change it retroactively, or just going forward? Is this a good business practice?  Any gotchas?

Content (required):

Our award template defaulted the burden schedule appropriately, but our end using department realized their mistake and wants to correct it. Expenditures have already been made against this project. We don't necessarily need to correct the info retroactively and changing the schedule would be far easier than ending existing awards and creating new ones with the correct burden schedule. We are a bit worried that doing so could result in some weird processing and or retro entries.