You can’t have your cake and eat it too.
If you have your cake and eat it too, you get two things that are normally impossible to get simultaneously.
Example: If you want more local services, you can’t expect to pay less tax. Well, you can’t have your cake and eat it.
Phrasal verb:back out
Back out | Fail to keep an arrangement or promise. | He BACKED OUT two days before the holiday so we gave the ticket to his sister |