Depends on the chord. There are certain chords that in order for them to be a true __ chord, you must play certain members. For example, a fully diminished chord must contain 1-b3-b5-bb7 in order to be called fully diminished. Anything more or less and you don't have a fully diminished chord.
On the other hand, there are chords where even if you omit a note, it is still considered a ___ chord. For example, the dominant 7th chord is made of 1-3-5-b7. The notes that must be played are 1-3-b7. The 5th may be omitted and you will still have a dominant 7th chord. Example:
C dominiant 7th chord (C7) = C-E-G-Bb
C / E-G-Bb-C
Let's take out the G:
C / E-Bb-C
Even without the G, you still have that C7 sound, so this is also considered to be a C7 chord. You will have to give me some specific chords in order for me to tell you what you need to play and what you can omit.