You really need to look at why they are changing the concept and wanting to switch to another startup.
If you are reluctant due to the time/effort already invested ("letting go" is a common problem), then perhaps what the others are suggesting is actually in your best interest(s) and doing you a favour.
If you are reluctant due to the time/effort already invested ("letting go" is a common problem), then perhaps what the others are suggesting is actually in your best interest(s) and doing you a favour.