وليس له تغيير حكم الشرع.
A person has no authority to alter a ruling laid down by the law.
One illustration concerns a stipulation in khulʿ: if the parties agree to waive both financial maintenance and residence during the waiting period, the discussion does not give the two provisions identical legal treatment.
In the Hanafi example cited, financial maintenance may be waived while the prohibition on expelling the woman from her waiting-period residence remains, since residence here includes a legal requirement not cancelled by a private condition.
Conclusion: some claims can be relinquished by their holders; others contain an independent legal right or restriction. Not every stipulation in a single agreement has the same effect.