Message type: E = Error
Message class:  CNV20551 - message for package 20551 (company code delete) 
Message number: 216
Message text: For ref. table field name &, reconciliation has already been maintained
Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.
To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.
Unfortunately, there isn't any extra information in this error notice.
First, use our AnswerBot below to get a possible cause and solution (requires a premium subscription).
Also, review the in-depth Common Questions & Answers listed below; you could discover a solution there or be able to connect with others who have faced similar challenges.
You can also try searching the SAP support portal (support.sap.com) but you need a special user ID to access it. It is possible that an SAP support note exists that provides additional details about the mistake or even steps for fixing it.
The SAP error message CNV20551216 indicates that there is an issue related to the reconciliation of a reference table field. This error typically arises during data migration or conversion processes, particularly when using SAP's data migration tools or during the execution of specific programs that involve data reconciliation.
Cause: The error message "For ref. table field name &, reconciliation has already been maintained" suggests that the reconciliation for the specified reference table field has already been set up or processed. This could happen due to: Duplicate Entries: The reconciliation process may have been executed multiple times for the same field, leading to conflicts. Incorrect Configuration: There may be a misconfiguration in the data migration settings or in the mapping of fields. Data Integrity Issues: The data being processed may have integrity issues, such as missing or incorrect references.
Solution: To resolve this error, you can take the following steps: Check Existing Reconciliation: Verify if the reconciliation for the
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV20551215 For field name &, reconciliation has already been maintained
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV20551214 Reference table & itself is a table with reconciliation logic
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV20551217 & is not defined in DDIC
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV20551218 For at least one table, the control table entries are inconsistent
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
Click on this link to search all SAP messages.