Yes, the everyday branding items are meant to be yours to change, so you do not need to raise a request every time you tweak your look. In the admin area you can normally upload your logo, set your main and secondary colours, change the site name, and edit things like the footer text and contact details that show on your pages. Once you save, the live site picks up the new look, which means a rebrand or a seasonal change can be done by someone in your office rather than waiting on anyone else.
There are limits worth knowing before you start. Your logo and colours usually appear in more than one place, so the booking pages, the confirmation emails, the vouchers and the invoice template may each need checking after a change, and some of those use their own templates. Anything structural, such as moving the search box, changing the page layout or adding a brand new page type, generally needs our team to help. How much of the look you can edit yourself also depends on your plan and on the theme your portal is built on, so it is fair to ask what is self service on your setup before you commit to a full rebrand.
A few practical habits save time. Upload a logo with a transparent background so it sits cleanly on both light and dark areas, check the result on a phone as well as a computer, and refresh your browser or clear its cache if the old version seems to linger. Emails already sent will keep the branding they had at the time, which is normal and not a fault.
Open the branding section of your admin area, make one small change, then run a test booking so you can see the new logo and colours on the site and on the confirmation your customer receives.