How to close an estimate ?

How to close an estimate ?

Hello,

I have created estimates, and converted them to invoices to get 50% payment.
Now I have 2 cases where the estimate stills shows status partially invoiced, however:
1. for one of them, project stopped half way, so the remaining part will never be invoiced. How can I "close" this estimate so  that it no longer appears in my "active" estimates ?
2. for one of them, I made 2 invoices of 50% each, but the estimate still shows "partially invoiced"; how can I make this estimate appear as "fully invoiced" ?

Thank you in advance