You could check that by attempting to make a new WTPart and use that exact same value for "Comments" and see if you get an error not allowing you to create it (or just use the brackets as the text). If you do, you could use the same method I suggested, but instead of deleting the record, just modify the value field(s) to remove the [ and ] characters.
Looking at the comparison report, it looks like the attribute is multi-valued. It would be a good try if you can remove the single value constraint on this attribute during off-hours and try the same steps again. You can revert the changes after the try.
I don't get any error on new parts getting created, even if I add in those brackets as text. I cannot delete the entire record. We just need to change the fields.
The attribute in the OIR and in the Type and Attribute Manager have the value as Single Valued Constraint. How do I remove it on this one record?
Parenthesis is displayed when the attribute has multiple values in the comparison report. On the details page these are displayed as comma separated. It is not possible to remove the constraint on a particular object. You may want to try removing the constraint on the part type when no one is accessing the system and remove the additional values from this particular part and finally put the constraint back.
The "single value" constraint is applied to the type, which then propagates to objects as they are created. While it is possible, it certainly isn't feasible to single out objects of a specific type to remove this constraint while others have it, without some serious DB modification.
What I would suggest is to use the steps I supplied above, and see if you an isolate the three records in the stringvalue table that construct this "entire" value. Modify one to be the "complete value", and then delete the other two. Thus, instead of removing the single value constraint, you actually consolidate the three values to one.
While Bhushan provides a good option, modifying the object type does NOT retroactively go back an update objects to the new type. If you remove the constraint in the Type and Attribute manager, all objects that were created WITH that constraint will continue to have it.
I would say even the approach mentioned by Bob should be safe as there are no other dependencies on string value table. I also tried the same behavior on 9.1 M050 server. Following are my observations
1. Created an multivalued attribute, created a part with 3 values and then added a single value constrain on the part type and tried edit options. I get the same error
2. Removed the single value constraint for a moment and tried editing the object, I can see all the values, remove all but one and I was able to check-in successfully. Re-added the constraint and the part has no issues now.