record has changed since you selected it

Hi Experts,

HPSM 9.30
I am doing integration between HPSM & an External Tool using WebServices (SOAP).
I am able to create a ticket in the External Tool & I am getting the ticket ID number. However when I try to add it to the interaction ticket in a field called externalID in HPSM, it's giving me this error message : This record has changed since you selected it. 
First I am retrieving the interaction ID (using Webservice)
Second I am creating a Ticket in the External Tool by using fields from the interaction (using webservice)
Then I am updating the interaction ID with the externalID that is pulled from the second step (also using webservices)

I thought retrieving the ticket is what causing this, however I removed the retrie ticket part and hardcoded the values, but with no luck. Whenever I reach the third step, it's throwing this error.

Anyone face this issue? 

Please let me know so I can fix it. 

Thanks