the person serves again
It is called a 'Let'
the umpire or the returner
A let is when the person serving serves the ball and it clips the net and then goes in. the server gets to re-serve
Anyone on that court in singles or doubles
In tennis, a let is where a player serves and the ball clips or brushes the top of the net chord and still lands in the serice box, and when this happens, the serve is played again without a fault taking effect in the scoring.
Net ball is called "Let" in table tennis. A Let occurs when a served ball hits the net and lands on the opponents side of the table. There is no penalty, the server just serves again.
If the ball bounces on the net and still bounces over to the opposing team of the server and in the correct box, a let, it is the reciever's call because the reciever must make all the calls for the tennis balls.
the term let in tennis is short for let it go
Do you mean "let"? If so, a let is when a serve touches/nicks the net AND lands in on a player's serve. People call "let" so the server knows their serve hit the net. If a server hits a let, they get to redo their serve.
There is no umpire in tennis.