PO not updating after Asset Master change

Hi All,

We want to change the Order field in Purchase Order screen under 'Account Assignment' tab, which normally will get derived from Asset Master.

Initially, It derived the same order what we have it in Asset Master. However, once PO got created and now we want to change it in Asset Master, it is not reflecting change in PO, infact it is greyed out.

Could someone from this forum please look into this and let me know the sol.

Thanks

Sri