Monks gain the Empty Body feature (PHB, page 79):

Beginning at 18th level, you can use your action to spend 4 ki points to become invisible for 1 minute. During that time, you also have resistance to all damage but force damage.

(...)

Confusion

"During that time" is a bit ambiguous to me. It implies that it's connected to the duration of one minute, but not necessarily to being invisible yet it isn't clear. However, this description doesn't mention any saves or concentration required for staying invisible, after taking damage for example. But since monks are all about controlling their own body and mind, it would make sense to me to become visible at will.

Is it possible to break the invisibility while keeping the resistances?

If so, how?

Being invisible for a minute can be handy, but as the sole frontliner of our party (bard, mystic, sorcerer) it's not always preferable in combat. Often I actually want the enemies to see me, but I wouldn't mind the resistances.

For this question I'm only interested in the RAW.

Strictly RAW

You become invisible for 1 minute. This is not like the invisibility spell; it is the invisible condition.

Invisible

• An invisible creature is impossible to see without the aid of magic or a special sense. For the purpose of hiding the creature is heavily obscured. The creature's location can be detected by any noise it makes or any tracks it leaves.




• Any attack rolls against the creature have disadvantage and the creature's attack rolls have advantage.

There is no concentration. There is no using an action to end it by RAW. Attacking does not end it. And it lasts 1 minute. During that time you have resistance to all damage but force.

It is not possible without DM permission to be visible. However, the enemy can still know where you are based off sound so just make sure the enemies hear you as you attack them. Thus you get resistance and it's hard to hit you.

"During that time" is ambiguous and up to DM interpretation.

It could be interpreted as "During the time you are invisible", but it could also be interpreted as "During that minute" and I cannot find a substantial reason to favor one interpretation over another.

Either way, Empty Body does not include a way to end its effects early, let alone end just one of the effects. However, in some specific circumstances a monk may be visible to all or some creatures even while the monk benefits from Empty Body's resistances.

Methods that work with "During the time you are invisible"

These methods involve negating the benefits of being invisible, without removing or suppressing the invisible condition, so a monk would still benefit from Empty Body's resistances. Here are two examples:

• Special senses such as truesight¹ and blindsight² allow a creature to perceive invisible creatures as though they were visible.


• 
  Faerie fire³ makes the monk unable to benefit from being invisible.

Methods that work with "During that minute"

These methods include all the above methods, plus any method that removes or suppresses the invisible condition. Here is one example:

• A Lantern of Revealing⁴ makes invisible creatures within its light visible.

1. PHB, page 185:
   
   

   
   

   A creature with truesight can, out to a specific range, see in normal and magical darkness, see invisible creatures and objects, automatically detect visual illusions and succeed on saving throws against them, and perceives the original form of a shapechanger or a creature that is transformed by magic. Furthermore, the creature can see into the Ethereal Plane.

   
   

   
   


2. PHB, page 183:
   
   

   
   

   A creature with blindsight can perceive its surroundings without relying on sight, within a specific radius. Creatures without eyes, such as oozes, and creatures with echolocation or heightened senses, such as bats and true dragons, have this sense.

   
   

   
   


3. PHB, page 239:
   
   

   
   

   Any attack roll against an affected creature or object has advantage if the attacker can see it, and the affected creature or
   object can't benefit from being invisible.

   
   

   
   


4. DMG, page 179:
   
   

   
   

   While lit, this hooded lantern burns for 6 hours on 1 pint of oil, shedding bright light in a 30-foot radius and dim light for an additional 30 feet. Invisible creatures and objects are visible as long as they are in the lantern's bright light. You can use an action to lower the hood, reducing the light to dim light in a 5-foot radius.