Message type: E = Error
Message class:  CNV20551 - message for package 20551 (company code delete) 
Message number: 748
Message text: Deletion criteria cannot be processed as &1 is present in No-Change table
The deletion criteria of the table cannot be changed as the table is
standard SAP table and SAP recommends the deletion criteria of this
table not to be changed.
The table is present in CNV_20551_NOCHAN table.
Error
Contact SAP if you want to change the deletion criteria of standard SAP
table.
The system issues an error message and will not allow you to continue with this transaction until the error is resolved.
Error message extract from SAP system. Copyright SAP SE.
The SAP error message CNV20551748 indicates that there is an issue with the deletion criteria in a data migration or conversion process. Specifically, it suggests that the system is unable to process the deletion criteria because a certain entry (denoted as &1) is present in the No-Change table. This typically occurs during data migration scenarios, such as when using the SAP S/4HANA Migration Cockpit or other data migration tools.
Cause: No-Change Table: The No-Change table is used to track records that should not be altered during the migration process. If an entry is present in this table, it means that the system has determined that this record should remain unchanged, which conflicts with the deletion criteria you are trying to apply. Data Integrity: The presence of the entry in the No-Change table may indicate that the data is critical or that it has dependencies that prevent it from being deleted.
Solution: Review the No-Change Table:
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