GillsBluenose
Vital Football Hero
Some contracts do have extension clauses WX.
It still needs both sides to agree it’s implementation.
If it was that mutual, there would be no point to such a clause, would there? Apart from perhaps like an alarm clock to remind both club and player.
Otherwise, just sign a new mutually agreeable contract when the other one is coming to an end.
In the EPL, you often read about a club exercising their "option" to extend a player's contract, either because they are playing well or to protect their value. That always sounds as if the club has the final say under the terms.