You can replace the return address, but if your main program makes calls to subroutines (placing return address to the stack) and/or makes pushes to the stack, there is nothing which would empty these from the stack so the stack will grow until it overflows.
Even worse, if this is a higher priority interrupt and interrupts a lower priority ISR, the latter will never finish and no lower priority interrupt will ever occur.

So under very well controlled circumstances this practice is possible, but a very risky business. I would strongly discourage to do so. You have been given a far better alternative by Erik.

Jan Waclawek