To replace an attached file in a proposal:
In a template, draft or new proposal, click 'Attachments'.
click 'Add attachment'.
Press 'replace' under the Attachment you wish to replace.
Select the new file by pressing 'upload attachment' and selecting the file you wish to add instead.
The old attachment will now be automatically replaced with the new file in all Templates and Drafts it appeared in.
Content Accounts
If you work with our content accounts, then by replacing the attachment in the content account, that attachment will automatically be replaced in all accounts that subscribe to the content account.