Does anyone know if there is change documents associated with the reservations screen MB21/MB22.

What I am after is an audit trail if a user raises a reservation and then decides that they wish to change the batch. I want to know who changed it, what that change was and the date and time of changing. 

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If the "Log data change" indicator checkbox is flagged for your related RESB table, then you can capture the change information including who carried out such change. 

I would assume that the 'Log Data Changes' indicator has not been activated in your table RESB. If this is activated, then any update can be seen in the log table of the database via Transaction SCU3. 
 

To set the "Log Changes Indicator" to be active on all reservations:

Go to Transaction SE11 and then click on 'Change' icon. 

In the next screen, click on 'Technical Settings' icon, the 'Log Data Change' indicator is located at the end of the screen. 
 

Notes:

Change logs are stored only when the concerned table (in this case RESB) has "Log Data Changes" box ticked (SE11-Technical settings). 

The standard SAP does not come with Reservation table log data checked. 

Once activated for RESB or any other table, you can probably check the changes in CDHDR/CDPOS tables besides SCU3 transaction. 

Go to SE11 and Input Table CDHDR and in Field list Input Transaction Code MB22 and Object Id as Reservation number in the Respective fields and Execute.

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