When custom field type is changed, the values stored in that field will be lost due to the change since most field types do not hold the same value.

Note: After field type was changed, logs on the System Notes will be deleted for this field due to the change so there will be no way of retrieving the value of the field.

Example 1: If custom field type is changed to Currency from Integer Number, New field has the value of old field.

Example 2: If a custom field type is changed to Integer Number from Phone Number, Old field value gets deleted.