you can't. although you could get your opponent to agree to repeat moves once to reset the clock
Extending length of daily games

I’m wondering if it is possible for players to mutually extend the length of a daily game. If so, how do you extend the time?
If it's a casual game, turn off the auto-claim setting for Daily on the website. It would need to get done for each player if both plan to take longer.
That said, premium members are going to be automatically placed on vacation when low on time in one or more games.
Also, the games will still automatically lose on time if no moves have been made in 60 days, even with that setting.

If you just need to extend it once then there’s the going on holiday mode. Might work.
Thanks @EddieKronstadt! Hope you’re doing well my friend.

I’m wondering if it is possible for players to mutually extend the length of a daily game. If so, how do you extend the time?
If it's a casual game, turn off the auto-claim setting for Daily on the website. It would need to get done for each player if both plan to take longer.
That said, premium members are going to be automatically placed on vacation when low on time in one or more games.
Also, the games will still automatically lose on time if no moves have been made in 60 days, even with that setting.
Thanks @Martin_Stahl. If one’s opponent does not have a premium membership the time would simply run out, correct?

It would sit at something like, < 1 minute, until the 69 days elapsed, a move was made, or you click the claim win option.
https://support.chess.com/article/514-how-can-i-prevent-getting-wins-based-on-timeouts
I’m wondering if it is possible for players to mutually extend the length of a daily game. If so, how do you extend the time?