How to backout revenue against an agreement.

We have 2 agreements for one project.  Agreement1 is entered wrongly and there is no funding on it and user forgot to end-date the agreement and revenue hard-limit is not there.  Agreement2 is created and is funded and has revenue hard limit of $100.

Now, the project has cost of $120.  When they generated the revenue, system generated two revenue entries one for $100 against Agreement1 and $20 against Agreement2.  User mistakenly released both of these revenues and accepted as well.

Now, we need to backout the $20 revenue and need to ene-date the Agreement.  How can we do this?  We are on R12.1.3