As far as I know right now only proposals sent through a job posting can have its terms changed after submission. Contracts proposed to existing/previous clients can not have their terms changed after submission, they can only be withdrawn. So you have to withdraw your proposed contract and send a new one even if all you want to do is adjust your rate/price. Do you plan on implementing this feature? It would be useful.
Thanks for sharing your feedback Burak!
Please note that while freelancers doesn't have the option to edit the proposed contract, clients can edit the freelancer’s proposal if needed and generate an offer to the freelancer. Have you had an experience in which the option to edit the proposed terms from your end was necessary in order to proceed with the client sending the offer from your proposal?
Please make sure to communicate with clients in order to ensure you agree on the terms for the new contract and note that we don't have plans for changing this feature in this respect.