When is validity need to retest if we made such changes in questionnaire?

let say i would like to use others researcher questionnaire, in my understanding, we do not need to re run the validity test. if :1. i change question

let say i would like to use others researcher questionnaire, in my understanding, we do not need to re run the validity test. if :
1. i change question language to others and simplify the meaning to suit my sample?
2. change the likert scale from 5 to 3?

or:let say i would like to use others researcher questionnaire, in my understanding, we do not need to re run the validity test. if :1. i change question language to others and simplify the meaning to suit my sample?2. change the likert scale from 5 to 3?

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