Changing date back one day with S9 autoset

[yankees123]

Don’t know how it happened but my s9 date is one day ahead.  
Have read other posts where they say all data can be erased and then can set date back.  
Anyone know an easy way to change the date back one day without erasing all data?  
Thanks

[jaswilliams]

Don’t know how it happened but my s9 date is one day ahead.  
Have read other posts where they say all data can be erased and then can set date back.  
Anyone know an easy way to change the date back one day without erasing all data?  
Thanks

In a word it's a pain. Time can only be set back after 12:00 PM (CPAP Time) and before the machine is used so before you use your machine tonight set the time back to 12:01 PM then at various time throughout the next few days until you reach the correct time, If you are not in a compliance period then import your data into sleepyhead/resscan, erase all data and reset date/time.

[gwc2795]

as jas said