Do You have access to the coat?
There are a few options to make the front dart dissappear:
Rotating the dart towards the lapel crease line to achieve a dart thatīs hidden under the lapel.
Rotating the dart towards the scye and easing the "dart" in secured with a harshly pulled chain stitch.
Rotating the dart in line with the pocket inserting line.
A combination of two or all of these options by dividing the dart amount.
In any case the dart will be shorter than the original one.
Here are pics of dartless jackets: