Timestream schema modification?

Hi, I'm trying to add some new records to one TS table, the problem I have is one of the measures is having the wrong data type (out of some test records happened earlier), the current measure type is BIGINT, what I'm trying to collect is a string VARCHAR type of data.\nHow can we change the table schema to accomudate the new measure values. I do understand the value type is immutable, but it would help if we get the test records removed or maybe the whole measure removed so we can start the new measure fresh and get it to be the right type?