Condition lists ending with 'R' are reserved for conversions

What causes this issue?

When converting accounts to variable transactions, the conditions of
the reference accounts are depicted using standard conditions in
condition lists. For all condition lists generated by the conversion,
the last character in the name is 'R'.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Error message extract from SAP system. Copyright SAP SE.