You can use "Add Column from Examples" option to enter the format you require in one or two records. It will detect automatically the required expected format and will populate for all other rows as well. Then replace the old column with new column.
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Both the methods mentioned here involves adding a new column. The reports that I'm working with have huge data, hence I think adding new columns for all date fields might cause performance issues , therefore is there any alternative method of directly changing the column format without adding a new column ?
This approach is useful, but since my data is large is there a way to do this without adding a new column and changing the existing column( such as how we change the format through modelling)as this might cause performance issues. Plus since this is a date field i would prefer it to remain the same as there are dependencies based on this column.