As such a change looms, it is up to the channel to find a suitable replacement and pray that viewers accept it. In some cases, the new actors are able to sustain the existing television rating points (TRPs) of the show, but sometimes the replacement becomes the reason for the downfall in TRPs.
"Half the battle is won if you have the right face and the other half is done by performance and attitude," Prashant Bhatt, fiction head of Colors channel, told.
Citing the example of Toral Rasputra replacing Pratyusha Banerjee or Anandi of "Balika Vadhu", Bhatt commented that was the risk they had to take.
"There were fears that the TRPs could drop, but there was no other option. We did not have a choice. Pratushya had made some other commitments and she wasn't ready to shoot for long hours," he added.
"When it comes to 'Balika Vadhu', we are very confident about our content. We did not want to compromise on it. I agree people will take some time to accept the new face. We have already started receiving good response for the new girl," said Bhatt.
There have been a few successful replacements in the past. Devoleena Bhattacharjee replaced Giaa Manek in "Saath Nibhana Saathiya" on Star Plus", Sharad Kelkar replaced Mohnish Behl in "Kuch Toh Log Kahenge" aired on Sony, and Hiten Tejwani replaced Sushant Singh Rajput in "Pavitra Rishta" on Zee TV.
But so far the most successful replacement was of Mihir Virani in "Kyunki... Saas Bhi Kabhi Thi", on Star Plus, where Amar Upadhyay was replaced by actor Rohit Roy.
On the other hand, in in the past, there were some TV shows yanked off air because the lead actors quit. "Iss Pyaar Ko Kya Naam Doon" was one such serial, where Barun Sobti, who had film offers, quit the show.
Then there is the pressure on the actor who steps into the shows of someone essaying the role of a popular character.
"I was nervous before taking the role. I know there is a lot of pressure on me to take the character forward since it is so popular. I hope I can up to the expectations of viewers.
"Even when Avika Gor as Anandi left the show and Pratyusha entered, there were apprehensions whether the viewers will accept the character," Toral told.
"Every actor who replaces someone looks for the viewers' support," she added.
Same is the case with actor Dheeraj Dhoopar, who replaced Shoaib Ibrahim in Color's show "Sasural Simar Ka" as Prem, husband of lead character Simar.
Dheeraj says it is a big challenge to replace someone so popular.
"Prem is a very popular character on TV. The show is doing good; TRP-wise also it is doing good. It has a good storyline. It's a very big challenge for me to replace someone who is so popular and connected with the audience," he said.
"I hope people like me too and continue to love Prem like they have been," said Dheeraj, last seen in TV show "Kuch Toh Log Kahenge".