Existing Series - Can this be converted to Integration Interface ?

Hi All,

7.3.0.2

1) We have a ediatble series -which user will manually enter the data. User  wants to uplaod the data in a spreadsheet.

Is this possible to develop an integration Interfaces for an existing Series..which currently is a ediatble series. I am thinking it is possible but wanted to reconfirm  with the group.

2) We have a Noneditable series. which is currently popullated by a custom program..User wants to convert this to a editable series to override the results. Systemdoes not allow this- The editable LOV is  greyed.  How can we make the Editable No to Yes.  We want to resue the same series.