Invalid call of PO change via function modules

What causes this issue?

The function modules for the fully automatic changing of purchase
orders have been invoked in the wrong sequence. The correct sequence
is:

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

ME_PURCHASE_DOCU_DATA_REFRESH
ME_PURCHASE_DOCUMENT_DATA_READ
ME_PUR_DOCU_HEADER_CHANGE
ME_PUR_DOCU_POSITION_CHANGE
ME_PURCHASE_DOCU_DATA_CHECK
ME_PURCHASE_DOCUMENT_DATA_SAVE
Data inconsistencies may be caused if this sequence is not adhered to.

System Response

How to fix this error?

Please bring the function module calls into line with the sequence
shown above.

Error message extract from SAP system. Copyright SAP SE.