This message is being written behalf of a friend of mine.
He is a Shia Momin. The concern is he did a temporary Nikkah (Mutah) with a girl & they both want to get married (permanent Nikkah) now, but there are still some months left before the end of the temporary Nikkah. Please advise what they should do. Is it possible to end the temporary nikkah with mutual understanding (because they want a permanent relationship), or is it mandatory to complete the time duration of the temporary nikkah, and then they can do a permanent nikkah? Also, if it is possible to end the temporary nikkah before the deadline so? Is there any specific procedure? Please let me know.

He can give the woman he performed temporary marriage with the time back and this will end the temporary marriage. The man can just terminate the temporary marriage, and if there is one month remaining, for example, he can just give it back to her. Then they can marry permanently