The first picture immediately above is from the OP. That one's probably a little trickier to get a smooth result as its small size and depth mean there's been some stretching of the material. You can easily see from the pattern of lacquer loss above it that there's been other previous dent work in the same general area. Someone was very very clumsy in handling this horn. I've known some hamfisted klutzes like that, like the guy I sometimes play with who constantly bangs his vintage Martin guitar down on the floor and against the metal legs of his chair.
The second picture is probably easier to get a smooth result as its more gentle contour means less stretching of the material. However, it'll be necessary to unsolder the guard strip. There's no lacquer left there anyway, so that's no biggie. That horn looks like it's had a lot of dent work down there as well.
It should be noted that neither of these dents will have ANY effect on the performance of the instrument and that removing them is purely an aesthetic decision.
The second picture is probably easier to get a smooth result as its more gentle contour means less stretching of the material. However, it'll be necessary to unsolder the guard strip. There's no lacquer left there anyway, so that's no biggie. That horn looks like it's had a lot of dent work down there as well.
It should be noted that neither of these dents will have ANY effect on the performance of the instrument and that removing them is purely an aesthetic decision.
