You can only edit objectives that you own. You can't edit an objective that you don't own even if you have a key result assigned to you in that objective.
Edit an objective
OKRs are not written in stone. During your cycle, it's ok to revise, add your objectives where you see fit.
Do the following steps to edit your objective:
Step 1: Go to the detail page of your objective
Step 2: Click on the Edit floating button
Step 3: Update the desired fields
Assignee: You can assign an objective to someone else other than yourself. You can also create an objective and assign to a department. Once saved, you will not be able to edit it if you assign it to others.
Due date: Choose the start and target end date. It's recommended to set a specific due date as you will more likely complete it.
Alignment: You can align this objective with another to create alignment. Your objective will contribute to the overall progress of the objective that you align to. It's recommended to align your objective to your team/department's objective or your line manager's objective.
Label: You can add one or more labels to your objective. Label helps to organize your objectives. Only admin can create labels.
Top company objective: If you are admin or workspace owner, you can set this objective to be the top company objectives.
Visibility: By default, objectives are public and it is recommended that way. However, you might want to set your objective to be private in situations such as: personal development goals, finance or legal related goals. If you set the objective to private, you can allow a team or other individuals to see it.
Edit/add key result
Click on a key result to edit it or Click on add a new key result to add a new one
Fill in the ownership, due date, start value, target metric and unit. You can create a custom unit such as: tickets, presentations, etc... It's recommended to choose a specific due date as it will be more likely that you will get it done on time.
Convert a key result to an objective: Click on the following icon to convert a key result to an objective
Step 5: Click on Submit to save.