A beautiful lapel roll is a sight to behold, one of the touchstones of a high-quality jacket. Unfortunately, some dry cleaners simply press lapels as flat as they can with a commercial press, destroying the roll. If you buy your jackets from a high-quality outfit, they may offer a “sponge & press” service, which involves hand-pressing the garment to its original shape. That service can be very tough to find these days, though, so it pays to know how to get that roll back at home.
To regain the shape of the lapel, StyleForum veteran Sator recommends the following procedure (which can, in my experience, also be roughly replicated with a steamer):

Try lying the coat down with the lapel lying flat, wrong side (the  underside of the lapels) upwards. The collar should be standing up - as  when you “pop” your collar. Place a press cloth over the roll of the lapel, near the buttoning point. A tea towel might do the trick. Lightly dampen the roll of the lapel. Press over the roll line near the buttoning point, ensuring you always iron with the press cloth under the iron. You may need to put a bit of downward force on it. In the tailoring  workshop you would use a heavy iron but you might just have to use a  strong arm. You may need to repeat this again the next day, especially if a heavy duty laundry press has been used on your lapel roll line.

A beautiful lapel roll is a sight to behold, one of the touchstones of a high-quality jacket. Unfortunately, some dry cleaners simply press lapels as flat as they can with a commercial press, destroying the roll. If you buy your jackets from a high-quality outfit, they may offer a “sponge & press” service, which involves hand-pressing the garment to its original shape. That service can be very tough to find these days, though, so it pays to know how to get that roll back at home.

To regain the shape of the lapel, StyleForum veteran Sator recommends the following procedure (which can, in my experience, also be roughly replicated with a steamer):

Try lying the coat down with the lapel lying flat, wrong side (the underside of the lapels) upwards. The collar should be standing up - as when you “pop” your collar.

Place a press cloth over the roll of the lapel, near the buttoning point. A tea towel might do the trick.

Lightly dampen the roll of the lapel.

Press over the roll line near the buttoning point, ensuring you always iron with the press cloth under the iron.

You may need to put a bit of downward force on it. In the tailoring workshop you would use a heavy iron but you might just have to use a strong arm.

You may need to repeat this again the next day, especially if a heavy duty laundry press has been used on your lapel roll line.