If you run into a situation where you have duplication of records, you are able to merge them into a single record. The process is the same for Contacts, Jobs, or Companies.
The below example is for merging two jobs
Starting the Merge process
Navigate into the job record
Select the drop down above the record name and then choose Merge With
Select the job you'd like to merge the record with
The Merge Dialog
The merge dialog will appear, allowing you to select what fields you want to merge to the final record. (The final record will be the record on the left side of the screen.)
View the record details for each record within the dialog
If there is data on the right side, you can merge it to the final record on the left by clicking on it.
The new field will display on the right, and flagged as "Merged"
Click Merge to complete the merge process.
As noted above, for companies and contacts, the process will look nearly identical.
On a contact record, you'll want to select This Contact
On the company record, you'll also see the merge after selecting the This Company drop down.