Is it possible for the admin to modify a contribution record amount for a Price Set field.
For example, if a user signs up and selects the contribution type/price, this seems static in the resulting contribution record.
I've found updating contribution amounts as Ramesh says is pretty weird for us, since we use price sets and offer lots of different deals and partnerships on events... the contribution status usually changes itself to partially paid or pending refund, which we don't want. I believe it's for people who want to use civicrm for financial reconciliation but since we dont, it makes things a bit complicated.
For one-offs, I usually go to the API explorer (yoursite.org/civicrm/api/explorer) and do a contribution create, including the contribution ID parameter to update the amount and the status (to completed) at the same time.
I guess you are trying to change the contribution amount
If so, you can change the contribution amount on it own and this is not going to affect the price set in anyway
I guess this helps !!!!